Isotopes of Cerium
Notable Isotopes
134
Ce [76 neutrons]
Abundance: synthetic
Half life: 3.16 days [ Electron Capture ]
Decay Energy: 0.500MeV
Decays to
136
134
La.
Ce [78 neutrons]
Abundance: 0.19%
Stable with 78 neutrons
138
Ce [80 neutrons]
Abundance: 0.25%
Stable with 80 neutrons
139
Ce [81 neutrons]
Abundance: synthetic
Half life: 137.640 days [ Electron Capture ]
Decay Energy: 0.278MeV
Decays to
140
139
La.
Ce [82 neutrons]
Abundance: 88.48%
Stable with 82 neutrons
141
Ce [83 neutrons]
Abundance: synthetic
Half life: 32.501 days [ beta- ]
Decay Energy: 0.581MeV
Decays to
142
141
Pr.
Ce [84 neutrons]
Abundance: 11.08%
Half life: 5 x 1016 years [ beta- ]
Decay Energy: ?MeV
Decays to
144
142
Nd.
Ce [86 neutrons]
Abundance: synthetic
Half life: 284.893 days [ beta- ]
Decay Energy: 0.319MeV
Decays to
144
Pr.
Cerium Compounds
Ammonium cerium(IV) nitrate
Cerium(IV) oxide
Ammonium cerium(IV) nitrate (NH4)2Ce(NO3)6
An important component of Chrome etchant, a material that is used in the production
of liquid crystal displays (LCDs).
Cerium(IV) oxide CeO2
It is used in ceramics, to polish glass, and to sensitize photosensitive glass. It is also
used in the walls of self-cleaning ovens.
Reactions of Cerium
Reactions with water
Cerium is quite electropositive and reacts slowly with cold water and quite quickly with
hot water to form cerium hydroxide and hydrogen gas.
2Ce(s) + 6H2O(g)
2Ce(OH)3(aq) + 3H2(g)
Reactions with air
Cerium tarnishes slowly in air and burns readily to form cerium (IV) oxide.
Ce + O2
CeO2
Reactions with halogens
Cerium metal reacts with all the halogens to form cerium(III) halides.
2Ce(s) + 3F2(g)
2CeF3(s)
2Ce(s) + 3Cl2(g)
2CeCl3(s)
2Ce(s) + 3Br2(g)
2CeBr3(s)
2Ce(s) + 3I2(g)
2CeI3(s)
Reactions with acids
Cerium dissolves readily in dilute sulphuric acid to form solutions containing the
colourless aquated Ce(III) ion together with hydrogen gas.
2Ce(s) + 3H2SO4(aq)
2Ce3+(aq) + 3SO42-(aq) + 3H2(g)
Reduction Potentials
Balanced half-reaction
Ce3+ + 3eCe(OH)2
Ce(OH)
2+
3+
E0 / V
Ce(s)
-2.48
+ 2H + e
+
Ce
-
+H +e
+
Ce
-
3+
3+
+ 2H2O
+ H2O
Ce(ClO4)62- + e-
Ce3+ + 6ClO4-
Ce(NO3)6
-
-
2-
+e
Ce
Ce(SO4)32-
+e
Ce
3+
3+
+1.73
+1.71
+1.70
+
6NO3-
+1.61
+
3SO42-
+1.44
Occurrence and Production of Cerium
Occurrence
Cerium is the most abundant of the rare earths elements, making up about 0.0046%
of the Earth's crust by weight. It is found in a number of minerals including allanite
(also known as orthite)-(Ca, Ce, La, Y)2(Al, Fe)3(SiO4)3(OH), monazite (Ce, La, Th, Nd,
Y)PO4, bastnasite(Ce, La, Y)CO3F, hydroxylbastnasite (Ce, La, Nd)CO3(OH, F),
rhabdophane (Ce, La, Nd)PO4 - H2O, zircon (ZrSiO4), and synchysite Ca(Ce, La, Nd,
Y)(CO3)2F. Monazite and bastnasite are presently the two most important sources of
cerium.
Cerium is most often prepared via an ion exchange process that uses monazite sands
as its cerium source.
Large deposits of monazite, allanite, and bastnasite will supply cerium, thorium, and
other rare-earth metals for many years to come.
Praseodymium [Pr]
CAS-ID: 7440-10-0
An: 59 N: 82
Am: 140.90765(2) g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white, yellowish tinge Classification: Metallic
Boiling Point: 3563K (3290°C)
Melting Point: 1208K (935°C)
Density: 6.77g/cm3
Discovery Information
Who: C.F. Aver von Welsbach
When: 1885
Where: Austria
Name Origin
Greek: prasios (green) and didymos (twin); from its green salts.
"Praseodymium" in different languages.
Sources
Can be found in rare earth minerals such as bastnasite and monazite. Obtained from
the same salts as neodymium.
Primary producers are the USA, Brazil, India, Sri Lank and Australia. Annual production
is around 2400 tons.
Abundance
Universe: 0.002 ppm (by weight)
Sun: 0.001 ppm (by weight)
Carbonaceous meteorite: 0.1 ppm
Earth's Crust: 8.7 ppm
Seawater:
Atlantic surface: 4 x 10-7 ppm
Atlantic deep: 7 x 10-7 ppm
Pacific surface: 4.4 x 10-7 ppm
Pacific deep: 1 x 10-6 ppm
Uses
Praseodymium forms the core of carbon arc lights which are used in the motion picture
industry for studio lighting and projector lights.
Used for colouring glass and ceramic glazes. Also used with neodymium to make
lenses for glass maker's goggles because they filter out the yellow light present in
glass blowing. It is alloyed with magnesium to create high strength metals.
History
In 1841, Mosander extracted the rare earth didymium from lanthana. In 1874, Per
Teodor Cleve concluded that didymium was in fact two elements, and in 1879, Lecoq
de Boisbaudran isolated a new earth, samarium, from didymium obtained from the
mineral samarskite. In 1885, the Austrian chemist baron Carl Auer von Welsbach
separated didymium into two elements, praseodymium and neodymium, which gave
salts of different colours.
Leo Moser investigated the use of praseodymium in glass colouration in the late 1920s.
The result was a yellow-green glass given the name "Prasemit". However, a similar
colour could be achieved with colourants costing only a minute fraction of what
praseodymium cost in the late 1920s, such that the colour was not popular, few pieces
were made, and examples are now extremely rare. Moser also blended praseodymium
with neodymium to produce "Heliolite" glass ("Heliolit" in German), which was more
widely accepted. The first enduring commercial use of praseodymium, which continues
today, is in the form of a yellow-orange stain for ceramics, "Praseodymium Yellow",
which is a solid-solution of praseodymium in the zirconium silicate (zircon) lattice. This
stain has no hint of green in it. By contrast, at sufficiently high loadings,
praseodymium glass is distinctly green, rather than pure yellow.
Praseodymium has historically been a rare earth whose supply has exceeded demand.
Unwanted as such, much praseodymium has been marketed as a mixture with
lanthanum and cerium, or "LCP" for the first letters of each of the constituents, for use
in replacing the traditional lanthanoid mixtures that were inexpensively made from
monazite or bastnaesite. LCP is what remains of such mixtures, after the desirable
neodymium, and all the heavier, rarer and more valuable lanthanoids have been
removed, by solvent extraction. However, as technology progresses, praseodymium
has been found possible to incorporate into neodymium-iron-boron magnets, thereby
extending the supply of the much in demand neodymium. So LC is starting to replace
LCP as a result.
Notes
Dr. Matthew Sellars of the Laser Physics Centre at the Australian National University in
Canberra, Australia slowed down a light pulse to a few hundred meters per second
using Praseodymium mixed with silicate crystal.
Hazards
Like all rare earth elements, praseodymium is of low to moderate toxicity.
Praseodymium has no known biological role.
Isotopes of Praseodymium
Notable Isotopes
141
Pr [82 neutrons]
Abundance: 100%
Stable with 82 neutrons
142
Pr [83 neutrons]
Abundance: synthetic
Half life: 19.12 hours [ beta- ] [ Electron Capture ]
Decay Energy: 2.1620.745MeV
Decays to
143
142
Nd142Ce.
Pr [84 neutrons]
Abundance: synthetic
Half life: 13.57 days [ beta- ]
Decay Energy: 0.934MeV
Decays to
143
Nd.
Reactions of Praseodymium
Reactions with water
Praseodymium is quite electropositive and reacts slowly with cold water and quite
quickly with hot water to form praseodymium hydroxide and hydrogen gas.
2Pr(s) + 6H2O(g)
2Pr(OH)3(aq) + 3H2(g)
Reactions with air
Praseodymium tarnishes slowly in air and burns readily to form a praseodymium oxide
which has the approximate formula Pr6O11.
12Pr(s) + 11O2(g)
2Pr6O11(s)
Reactions with halogens
Praseodymium reacts with all the halogens to form praseodymium(III) halides.
2Pr(s) + 3F2(g)
2PrF3(s)
2Pr(s) + 3Cl2(g)
2PrCl3(s)
2Pr(s) + 3Br2(g)
2PrBr3(s)
2Pr(s) + 3I2(g)
2PrI3(s)
Reactions with acids
Praseodymium dissolves readily in dilute sulphuric acid to form solutions containing the
green aquated Pr(III) ion together with hydrogen gas.
2Pr(s) + 3H2SO4(aq)
2Pr3+(aq) + 3SO42-(aq) + 3H2(g)
141
Pr
Neodymium [Nd]
CAS-ID: 7440-00-8
An: 60 N: 84
Am: 144.24 g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white, yellowish tinge Classification: Metallic
Boiling Point: 3373K (3100°C)
Melting Point: 1297K (1024°C)
Density: 7.01g/cm3
Discovery Information
Who: C.F. Aver von Welsbach
When: 1925
Where: Austria
Name Origin
Greek: neos (new) didymos (twin).
"Neodymium" in different languages.
Sources
Neodymium is never found in nature as the free element. It occurs in ores such as
monazite sand and bastnasite.
Primary producers are the USA, Brazil, India, Sri Lanka and Australia. Around 7300
tons are produced annually.
Abundance
Universe: 0.01 ppm (by weight)
Sun: 0.003 ppm (by weight)
Carbonaceous meteorite: 0.51 ppm
Earth's Crust: 33 ppm
Seawater:
Atlantic surface: 1.8 x 10-6 ppm
Atlantic deep: 3.2 x 10-6 ppm
Pacific surface: 1.8 x 10-6 ppm
Pacific deep: 4.8 x 10-6 ppm
Uses
Used in ceramics to colour glazes, and for special lens with praseodymium. Also to
produce bright purple glass and special glass that filters infrared radiation. Neodymium
is used in very powerful permanent magnets - Nd2Fe14B. These magnets are cheaper
and also stronger than samarium-cobalt magnets. Neodymium magnets appear in
products such as in-ear headphones and computer hard drives.
History
Neodymium was discovered by Baron Carl Auer von Welsbach, an Austrian chemist, in
Vienna in 1885. He separated neodymium, as well as the element praseodymium, from
a material known as didymium by means of fractional crystallization of the double
ammonium nitrate tetrahydrates from nitric acid, while following the separation by
spectroscopic analysis; however, it was not isolated in relatively pure form until 1925.
The name neodymium is derived from the Greek words neos, new, and didymos, twin.
Neodymium is frequently misspelled as neodynium.
Double nitrate crystallization was the means of commercial neodymium purification
until the 1950's. The Lindsay Chemical Division of American Potash and Chemical
Corporation, at one time the largest producer of rare earths in the world, offered
neodymium oxide purified in this manner in grades of 65%, 85% and 95% purity, at
prices ranging from approximately 2 to 20 dollars per pound (in 1960 dollars). Lindsay
was the first to commercialize large-scale ion-exchange purification of neodymium,
using the technology developed by Frank Spedding at Iowa State University/Ames
Laboratory; one pound of their 99% oxide was priced at $35 in 1960; their 99.9%
grade only cost 5 dollars more. Starting in the 1950's, high purity (e.g. 99+%)
neodymium was primarily obtained through an ion exchange process from monazite
sand ((Ce,La,Th,Nd,Y)PO4), a material rich in rare earth elements. The metal itself is
obtained through electrolysis of its halide salts. Currently, most neodymium is
extracted from bastnaesite, (Ce,La,Nd,Pr)CO3F, and purified by solvent extraction. Ionexchange purification is reserved for preparing the highest purities (typically greater
than 4N). (When Molycorp first introduced their 98% grade of neodymium oxide in
1965, made by solvent extraction from Mountain Pass California bastnaesite, it was
priced at 5 dollars per pound, for small quantities. Lindsay soon discontinued
operations.) The evolving technology, and improved purity of commercially available
neodymium oxide was reflected in the appearance of neodymium glass made
therefrom, that resides in collections today. Early Moser pieces, and other neodymium
glass made in the 1930's, have a more reddish or orange tinge than modern versions,
which are more cleanly purple, due to the difficulties in removing the last traces of
praseodymium, when the fractional crystallization technology had to be relied on.
Notes
Size and strength of volcanic eruption can be predicted by scanning for neodymium
isotopes. Small and large volcanic eruptions produce lava with different neodymium
isotope composition. From the composition of isotopes, scientists predict how big the
coming eruption will be, and use this information to warn residents of the intensity of
the eruption.
Hazards
Neodymium metal dust is a combustion and explosion hazard. Neodymium dust and
salts are very irritating to the eyes and mucous membranes, and moderately irritating
to skin. Breathing the dust can cause lung embolisms, and accumulated exposure
damages the liver. Neodymium also acts as an anticoagulant, especially when given
intravenously. Neodymium compounds, like all rare earth metals, are of low to
moderate toxicity; however its toxicity has not been thoroughly investigated.
Isotopes of Neodymium
Notable Isotopes
142
Nd [82 neutrons]
Abundance: 27.13%
Stable with 82 neutrons
143
Nd [83 neutrons]
Abundance: 12.18%
Stable with 83 neutrons
144
Nd [84 neutrons]
Abundance: 23.8%
Half life: 2.29 x 1015 years [ Alpha Decay ]
Decay Energy: 1.905MeV
Decays to
145
140
Ce.
Nd [85 neutrons]
Abundance: 8.3%
Stable with 85 neutrons
146
Nd [86 neutrons]
Abundance: 17.19%
Stable with 86 neutrons
148
Nd [88 neutrons]
Abundance: 5.76%
Stable with 88 neutrons
150
Nd [90 neutrons]
Abundance: 5.64%
Half life: 1.1 x 1019 years [ Double beta decay ]
Decay Energy: 3.367MeV
Decays to
Sm.
150
Reactions of Neodymium
Reactions with water
Neodymium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form neodymium hydroxide and hydrogen gas.
2Nd(s) + 6H2O(g)
2Nd(OH)3(aq) + 3H2(g)
Reactions with air
Neodymium tarnishes slowly in air and burns readily to form neodymium (III) oxide.
4Nd + 3O2
2Nd2O3
Reactions with halogens
Neodymium reacts with all the halogens to form neodymium(III) halides.
2Nd(s) + 3F2(g)
2NdF3(s)
2Nd(s) + 3Cl2(g)
2NdCl3(s)
2Nd(s) + 3Br2(g)
2NdBr3(s)
2Nd(s) + 3I2(g)
2NdI3(s)
Reactions with acids
Neodymium dissolves readily in dilute sulphuric acid to form solutions containing the
lilac aquated Nd(III) ion together with hydrogen gas.
2Nd(s) + 3H2SO4(aq)
2Nd3+(aq) + 3SO42-(aq) + 3H2(g)
Promethium [Pm]
CAS-ID: 7440-12-2
An: 61 N: 84
Am: [145] g/mol
Group Name: Lanthanoids
Block: f-block
Period: 6 (lanthanoid)
State: solid at 298 K
Colour: metallic Classification: Metallic
Boiling Point: 3273K (3000°C)
Melting Point: 1373K (1100°C)
Density: 7.26g/cm3
Discovery Information
Who: J.A. Marinsky, L.E. Glendenin, C.D. Coryell
When: 1945
Where: United States
Name Origin
From Prometheus who stole the fire of the sky and gave it to mankind.
"Promethium" in different languages.
Sources
Does not occur naturally. Found among fission products of uranium, thorium, and
plutonium.
Uses
Used as a radiation source in thickness gauges, photoelectric cells and hold potential
as a heat source for auxiliary power in satellites. In a nuclear battery in which
photocells convert the light into electric current, yielding a useful life of about five
years using 147Pm.
History
The existence of promethium was first predicted by Bohuslav Brauner in 1902; this
prediction was supported by Henry Moseley in 1914, who found a gap for a missing
element which would have atomic number 61, but was unknown (however, Moseley of
course had no sample of the element to verify this). Several groups claimed to have
produced the element, but they could not confirm their discoveries because of the
difficulty of separating promethium from other elements. Promethium was first
produced and proved to exist at Oak Ridge National Laboratory (ORNL) in 1945 by
Jacob A. Marinsky, Lawrence E. Glendenin and Charles D. Coryell by separation and
analysis of the fission products of uranium fuel irradiated in the Graphite Reactor;
however, being too busy with defense-related research during World War II, they did
not announce their discovery until 1947. The name promethium is derived from
Prometheus in Greek mythology, who stole the fire of the sky and gave it to mankind.
The name was suggested by Grace Mary Coryell, Charles Coryell's wife, who felt that
they were stealing fire from the gods.
In 1963, ion-exchange methods were used at ORNL to prepare about 10 grams of
promethium from nuclear reactor fuel processing wastes.
Today, promethium is still recovered from the byproducts of uranium fission; it can
also be produced by bombarding 146Nd with neutrons, turning it into 147Nd which
decays into 147Pm through beta decay with a half-life of 11 days.
Notes
Promethium is also the name of a fictional element in the DC Universe; writer Marv
Wolfman claims to have been unaware of the existence of a real substance by that
name at the time he wrote the original script featuring the name.
Hazards
Promethium must be handled with great care because of its high radioactivity.
Isotopes of Promethium
Notes
Promethium has no stable isotopes.
Notable Isotopes
145
Pm [84 neutrons]
Abundance: synthetic
Half life: 17.7 years [ Electron Capture ]
Decay Energy: 0.163MeV
Decays to
146
145
Nd.
Pm [85 neutrons]
Abundance: synthetic
Half life: 5.53 years [ Electron Capture ]
Decay Energy: 1.472MeV
Decays to
146
Nd.
Half life: 5.53 years [ beta- ]
Decay Energy: 1.542MeV
Decays to
147
Sm.
146
Pm [86 neutrons]
Abundance: synthetic
Half life: 2.6234 years [ beta- ]
Decay Energy: 0.224MeV
Decays to
Sm.
147
Reactions of Promethium
Reactions with acids
Promethium dissolves readily in dilute sulphuric acid to form solutions containing the
pink aquated Pm(III) ion together with hydrogen gas.
2Pm(s) + 3H2SO4(aq)
2Pm3+(aq) + 3SO42-(aq) + 3H2(g)
Samarium [Sm]
CAS-ID: 7440-19-9
An: 62 N: 88
Am: 150.36 g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 2076K (1803°C)
Melting Point: 1345K (1072°C)
Density: 7.52g/cm3
Discovery Information
Who: Paul emile Lecoq de Boisbaudran
When: 1879
Where: France
Name Origin
From the mineral samarskite, named after a Russian mine official, Colonel Samarski.
"Samarium" in different languages.
Sources
Never found free in nature. Samarium is found in many minerals, including bastnasite,
monazite and samarskite.
Primary producers are the USA, Brazil, India, Sri Lanka and Australia. Around 700 tons
are produced annually.
Abundance
Universe: 0.005 ppm (by weight)
Sun: 0.001 ppm (by weight)
Carbonaceous meteorite: 0.17 ppm
Earth's Crust: 6 ppm
Seawater:
Atlantic surface: 4 x 10-7 ppm
Atlantic deep: 6.4 x 10-7 ppm
Pacific surface: 4 x 10-7 ppm
Pacific deep: 1 x 10-6 ppm
Uses
Used in carbon-arc lighting, permanent magnets, lasers, alloys, headphones and as an
absorber in nuclear reactors.
Samarium oxide is used in optical glass to absorb infrared.
Samarium-Cobalt magnets; SmCo5 is used in making a new permanent magnet
material with the highest resistance to demagnetization of any known material.
History
Samarium was first discovered spectroscopically in 1853 by Swiss chemist Jean
Charles Galissard de Marignac by its sharp absorption lines in didymium, and isolated
in Paris in 1879 by French chemist Paul Emile Lecoq de Boisbaudran from the mineral
samarskite ((Y,Ce,U,Fe)3(Nb,Ta,Ti)5O16). Although samarskite was first found in the
Urals, by the late 1870s a new deposit had been located in North Carolina, and it was
from that source that the samarium-bearing didymium had originated.
The samarskite mineral was named after Vasili Samarsky-Bykhovets, the Chief of Staff
(Colonel) of the Russian Corps of Mining Engineers in 1845-1861. The name of the
element is derived from the name of the mineral, and thus traces back to the name
Samarsky-Bykhovets. In this sense samarium was the first chemical element to be
named after a living person.
Prior to the advent of ion-exchange separation technology in the 1950s, samarium had
no commercial uses in pure form. However, a by-product of the fractional
crystallization purification of neodymium was a mixture of samarium and gadolinium
that acquired the name of "Lindsay Mix" after the company that made it. This material
is thought to have been used for nuclear control rods in some of the early nuclear
reactors. Nowadays, a similar commodity product goes under the name of "SamariumEuropium-Gadolinium" concentrate (or SEG concentrate). This is prepared by solvent
extraction from the mixed lanthanoids extracted from bastnaesite (or monazite). Since
the heavier lanthanoids have the greater affinity for the solvent used, they are easily
extracted from the bulk using relatively small proportions of solvent. Not all rare earth
producers who process bastnaesite do so on large enough scale to continue onward
with the separation of the components of SEG, which typically makes up only one or
two percent of the original ore. Such producers will therefore be making SEG with a
view to marketing it to the specialized processors. In this manner, the valuable
europium content of the ore is rescued for use in phosphor manufacture. Samarium
purification follows the removal of the europium. Currently, being in oversupply,
samarium oxide is less expensive on a commercial scale than its relative abundance in
the ore might suggest.
Isotopes of Samarium
Notable Isotopes
Sm [82 neutrons]
144
Abundance: 3.07%
Stable with 82 neutrons
Sm [84 neutrons]
146
Abundance: synthetic
Half life: 1.03 x 108 years [ Alpha Decay ]
Decay Energy: 2.529MeV
Decays to
142
Nd.
Sm [85 neutrons]
147
Abundance: 14.99%
Half life: 1.06 x 1011 years [ Alpha Decay ]
Decay Energy: 2.310MeV
Decays to
143
Nd.
Sm [86 neutrons]
148
Abundance: 11.24%
Half life: 7 x 1015 years [ Alpha Decay ]
Decay Energy: 1.986MeV
Decays to
144
Nd.
Sm [87 neutrons]
149
Abundance: 13.82%
Half life: 2 x 1015 years [ Alpha Decay ]
Decay Energy: 1.870MeV
Decays to
145
Nd.
Sm [88 neutrons]
150
Abundance: 7.38%
Stable with 88 neutrons
Sm [90 neutrons]
152
Abundance: 26.75%
Stable with 90 neutrons
Sm [92 neutrons]
154
Abundance: 22.75%
Stable with 92 neutrons
Reactions of Samarium
Reactions with water
Samarium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form samarium hydroxide and hydrogen gas.
2Sm(s) + 6H2O
2Sm(OH)3(aq) + 3H2(g)
Reactions with air
Samarium tarnishes slowly in air and burns readily to form samarium (III) oxide.
4Sm(s) + 3O2(g)
2Sm2O3(s)
Reactions with halogens
Samarium reacts with all the halogens to form samarium(III) halides.
2Sm(s) + 3F2(g)
2SmF3(s)
2Sm(s) + 3Cl2(g)
2SmCl3(s)
2Sm(s) + 3Br2(g)
2SmBr3(s)
2Sm(s) + 3I2(g)
2SmI3(s)
Reactions with acids
Samarium dissolves readily in dilute sulphuric acid to form solutions containing the
yellow aquated Sm(III) ion together with hydrogen gas.
2Sm(s) + 3H2SO4(aq)
2Sm3+(aq) + 3SO42-(aq) + 3H2(g)
Europium [Eu]
CAS-ID: 7440-53-1
An: 63 N: 89
Am: 151.964 (1) g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 1800K (1527°C)
Melting Point: 1099K (826°C)
Density: 5.244g/cm3
Discovery Information
Who: Eugene Demarcay
When: 1901
Where: France
Name Origin
From Europe.
"Europium" in different languages.
Sources
It is never found in nature as a free element. There are many minerals that contain
europium, the important of these are bastnasite and monazite.
Primary mining locations are the USA, Brazil, India, Sri Lanka, Australia and China.
Annual production is around 400 tons.
Abundance
Universe: 0.0005 ppm (by weight)
Sun: 0.0005 ppm (by weight)
Carbonaceous meteorite: 0.006 ppm
Earth's Crust: 2.1 ppm
Seawater:
Atlantic surface: 9 x 10-8 ppm
Atlantic deep: 1.5 x 10-7 ppm
Pacific surface: 1 x 10-7 ppm
Pacific deep: 2.7 x 10-7 ppm
Uses
Europium oxide (Eu2O3) along with yttrium oxide are used to make red phosphors for
colour televisions. A salt of Europium is a component of the newer phosphorescent
powders and paints, some of which will glow for days after a few minutes of exposure
to light.
A salt of Europium is a component of the newer phosphorescent powders and paints,
some of which will glow for days after a few minutes of exposure to light. Europium
fluorescence is used to interogate biomolecular interactions in drug-discovery screens.
It is also used in the anti-counterfeiting phosphors in Euro banknotes.
History
Europium was first found by Paul Emile Lecoq de Boisbaudran in 1890, who obtained
basic fraction from samarium-gadolinium concentrates which had spectral lines not
accounted for by samarium or gadolinium; however, the discovery of europium is
generally credited to French chemist Eugene-Anatole Demarcay, who suspected
samples of the recently discovered element samarium were contaminated with an
unknown element in 1896 and who was able to isolate europium in 1901. When the
europium-doped yttrium orthovanadate red phosphor was discovered in the early
1960s, and understood to be about to cause a revolution in the colour television
industry, there was a mad scramble for the limited supply of europium on hand among
the monazite processors. (Typical europium content in monazite was about 0.05%.)
Luckily, Molycorp, with its bastnaesite deposit at Mountain Pass California, whose
lanthanoids had an unusually "rich" europium content of 0.1%, was about to come online and provide sufficient europium to sustain the industry. Prior to europium, the
colour-TV red phosphor was very weak, and the other phosphor colours had to be
muted, to maintain colour balance. With the brilliant red europium phosphor, it was no
longer necessary to mute the other colours, and a much brighter colour TV picture was
the result. Europium has continued in use in the TV industry ever since, and, of course,
also in computer monitors. California bastnaesite now faces stiff competition from
Bayan Obo, China, with an even "richer" europium content of 0.2%. Frank Spedding,
celebrated for his development of the ion-exchannge technology that revolutionized
the rare earth industry in the mid-1950's once related the story of how, in the 1930's,
he was lecturing on the rare earths when an elderly gentleman approached him with
an offer of a gift of several pounds of europium oxide. This was an unheard-of quantity
at the time, and Spedding did not take the man seriously. However, a package duly
arrived in the mail, containing several pounds of genuine europium oxide. The elderly
gentleman had turned out to be the Dr. McCoy who had developed a famous method of
europium purification involving redox chemistry.
Notes
Europium is the most reactive of the rare earth elements; it quickly oxidizes in air, and
resembles calcium in its reaction with water. It is about as hard as lead and quite
ductile.
Hazards
As dust, europium presents a fire and explosion hazard.
Isotopes of Europium
Notable Isotopes
150
Eu [87 neutrons]
Abundance: synthetic
Half life: 36.9 years [ Electron Capture ]
Decay Energy: 2.261MeV
Decays to
Sm.
150
151
Eu [88 neutrons]
Abundance: 47.8%
Stable with 88 neutrons
152
Eu [89 neutrons]
Abundance: synthetic
Half life: 13.516 years [ Electron Capture ]
Decay Energy: 1.874MeV
Decays to
Sm.
152
Half life: 13.516 years [ beta- ]
Decay Energy: 1.819MeV
Decays to
153
152
Gd.
Eu [90 neutrons]
Abundance: 52.2%
Stable with 90 neutrons
Reactions of Europium
Reactions with water
Europium is quite electropositive and reacts slowly with cold water and fairly quickly
with hot water to form europium hydroxide, and hydrogen gas.
2Eu(s) + 6H2O(g)
2Eu(OH)3(aq) + 3H2(g)
Reactions with air
Europium metal burns readily in air to form europium(III) oxide.
4Eu + 3O2
2Eu2O3
Reactions with halogens
Europium metal reacts with all the halogens to form europium(III) halides.
2Eu(s) + 3F2(g)
2EuF3(s)
2Eu(s) + 3Cl2(g)
2EuCl3(s)
2Eu(s) + 3Br2(g)
2EuBr3(s)
2Eu(s) + 3I2(g)
2EuI3(s)
Reactions with acids
Europium metal dissolves readily in dilute sulphuric acid to form solutions containing
the very pale pink Eu(III) ion together with hydrogen gas.
2Eu(s) + 3H2SO4(aq)
2Eu3+(aq) + 3SO42-(aq) + 3H2(g)
Gadolinium [Gd]
CAS-ID: 7440-54-2
An: 64 N: 93
Am: 157.25 g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 3523K (3250°C)
Melting Point: 1585K (1312°C)
Superconducting temperature: 1.083K (-272.067°C)
Density: 7.90g/cm3
Discovery Information
Who: Jean de Marignac
When: 1880
Where: Switzerland
Name Origin
Named after the Finnish chemist and geologist Johan Gadolin.
"Gadolinium" in different languages.
Sources
Gadolinium is never found in nature in elemental form. It is obtained from many rare
minerals such as bastnasite, monazite and trace amounts in gadolinite.
Primary mining deposits are located in the USA, Brazil, India, Sri Lanka, Australia and
Chine. Annual production is around 400 tons.
Abundance
Universe: 0.002 ppm (by weight)
Sun: 0.002 ppm (by weight)
Carbonaceous meteorite: 0.23 ppm
Earth's Crust: 7.7 ppm
Seawater:
Atlantic surface: 5.2 x 10-7 ppm
Atlantic deep: 9.3 x 10-7 ppm
Pacific surface: 6 x 10-7 ppm
Pacific deep: 1.5 x 10-6 ppm
Uses
Compounds of gadolinium are used in making phosphors for colour TV tubes and in the
manufacture of compact discs and computer memory. Gallium Gadolinium Garnet
(Gd3Ga5O12) is a material with good optical properties, and is used in fabrication of
various optical components and as substrate material for magneto-optical films.
Gadolinium is used for making gadolinium yttrium garnets, which have microwave
applications.
Solutions of organic gadolinium complexes are used as intravenous radiocontrast
agents to enhance images in medical magnetic resonance imaging. Because of their
paramagnetic properties, gadolinium compounds are used in magnetic resonance
imaging (MRI).
History
In 1880, Swiss chemist Jean Charles Galissard de Marignac observed spectroscopic
lines due to gadolinium in samples of didymium and gadolinite; French chemist Paul
Emile Lecoq de Boisbaudran separated gadolinia, the oxide of Gadolinium, from
Mosander's yttria in 1886. The element itself was isolated only recently.
In older literature the natural form of the element is often called an "earth", meaning
that element came from the Earth. Accordingly - Gadolinium is the element that comes
from the earth, gadolinia. Earths are compounds of the element and one or more other
elements. Two common combining elements are oxygen and sulfur. For example,
gadolinia contains gadolinium oxide (Gd2O3).
Notes
Gadolinium becomes superconductive below a critical temperature of 1.083 K (272.067°C). It is strongly magnetic at room temperature.
Hazards
As with the other lanthanoids, gadolinium compounds are of low to moderate toxicity,
although their toxicity has not been investigated in detail.
Powder may react with water or moisture. The powder is highly flammable.
Isotopes of Gadolinium
Notable Isotopes
152
Gd [88 neutrons]
Abundance: 0.20%
Half life: 1.08 x 1014 years [ Alpha Decay ]
Decay Energy: 2.205MeV
Decays to
154
Sm.
148
Gd [90 neutrons]
Abundance: 2.18%
Stable with 90 neutrons
155
Gd [91 neutrons]
Abundance: 14.80%
Stable with 91 neutrons
156
Gd [92 neutrons]
Abundance: 20.47%
Stable with 92 neutrons
157
Gd [93 neutrons]
Abundance: 15.65%
Stable with 93 neutrons
158
Gd [94 neutrons]
Abundance: 24.84%
Stable with 94 neutrons
160
Gd [96 neutrons]
Abundance: 21.86%
Half life: 1.3 x 1021 years [ Double beta decay ]
Decay Energy: 1.7MeV
Decays to
160
Dy.
Reactions of Gadolinium
Reactions with water
Gadolinium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form gadolinium hydroxide, Gd(OH)3, and hydrogen gas (H2).
2Gd(s) + 6H2O(g)
2Gd(OH)3(aq) + 3H2(g)
Reactions with air
Gadolinium metal burns readily in air to form Gadolinium(III) oxide.
4Gd(s) + 3O2(g)
2Gd2O3
Reactions with halogens
Gadolinium metal reacts with all the halogens to form gadolinium(III) halides.
2Gd(s) + 3F2(g)
2GdF3(s)
2Gd(s) + 3Cl2(g)
2GdCl3(s)
2Gd(s) + 3Br2(g)
2GdBr3(s)
2Gd(s) + 3I2(g)
2GdI3(s)
Reactions with acids
Gadolinium metal dissolves readily in dilute sulphuric acid to form solutions containing
the Gd(III) ion together with hydrogen gas.
2Gd(s) + 3H2SO4(aq)
2Gd3+(aq) + 3SO42-(aq) + 3H2(g)
Dysprosium [Dy]
CAS-ID: 7429-91-6
An: 66 N: 96
Am: 162.500 (1) g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 2840K (2567°C)
Melting Point: 1680K (1407°C)
Density: 8.540g/cm3
Discovery Information
Who: Paul emile Lecoq de Boisbaudran
When: 1886
Where: France
Name Origin
Greek: dysprositos (hard to get at).
"Dysprosium" in different languages.
Sources
Dysprosium is never encountered as the free element. Usually found with erbium,
holmium and other rare earths in some minerals (euxenite
((Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6), fergusonite ((Ce,La,Nd)NbO4), gadolinite
((Ce,La,Nd,Y)2FeBe2Si2O10) and xenotime to name a few).
Around 100 tons are produced annually. Primary mining occurs in the USA, Brazil,
India, Sri Lanka and Australia.
Abundance
Universe: 0.002 ppm (by weight)
Sun: 0.002 ppm (by weight)
Carbonaceous meteorite: 0.28 ppm
Earth's Crust: 6 ppm
Seawater:
Atlantic surface: 8 x 10-7 ppm
Atlantic deep: 9.6 x 10-7 ppm
Pacific surface: n/a ppm
Pacific deep: n/a ppm
Uses
Dysprosium is used for manufacturing compact discs, and in conjunction with
vanadium and other elements is used in making laser materials.
As control-rods for nuclear reactors because it readily absorbs neutrons.
History
Dysprosium was first identified in Paris in 1886 by French chemist Paul Emile Lecoq de
Boisbaudran. However, the element itself was not isolated in relatively pure form until
after the development of ion exchange and metallographic reduction techniques in the
1950s. The name dysprosium is derived from the Greek "dysprositos"; "hard to
obtain". Part of the difficulty lay in dysprosium being especially close in its behavior to
the far more abundant yttrium, during many of the separation technologies that were
used in the 19th century. This overshadowed the fact that dysprosium was the most
abundant of the heavy lanthanoids.
Notes
It is soft enough to be cut with a knife, and can be machined without sparking if
overheating is avoided. Dysprosium's characteristics can be greatly affected even by
small amounts of impurities.
It wasn't until the 1950s that the element was isolated in a relatively pure form.
Dysprosium does not have any known biological properties.
Hazards
As with the other lanthanoids, dysprosium compounds are of low to moderate toxicity,
although their toxicity has not been investigated in detail.
Isotopes of Dysprosium
Notable Isotopes
154
Dy [89 neutrons]
Abundance: synthetic
Half life: 3.0 x 106 years
156
Dy [90 neutrons]
Abundance: 0.06%
Stable with 90 neutrons
158
Dy [92 neutrons]
Abundance: 0.10%
Stable with 92 neutrons
160
Dy [94 neutrons]
Abundance: 2.34%
Stable with 94 neutrons
161
Dy [95 neutrons]
Abundance: 18.91%
Stable with 95 neutrons
162
Dy [96 neutrons]
Abundance: 25.51%
Stable with 96 neutrons
163
Dy [97 neutrons]
Abundance: 24.90%
Stable with 97 neutrons
164
Dy [98 neutrons]
Abundance: 28.18%
Stable with 98 neutrons
Reactions of Dysprosium
Reactions with water
Dysprosium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form dysprosium hydroxide and hydrogen gas.
2Dy(s) + 6H2O(g)
2Dy(OH)3(aq) + 3H2(g)
Reactions with air
Dysprosium tarnishes slowly in air and burns readily to form dysprosium (III) oxide.
4Dy(s) + 3O2(g)
2Dy2O3(s)
Reactions with halogens
Dysprosium reacts with all the halogens to form dysprosium(III) halides.
2Dy(s) + 3F2(g)
2DyF3(s)
2Dy(s) + 3Cl2(g)
2DyCl3(s)
2Dy(s) + 3Br2(g)
2DyBr3(s)
2Dy(s) + 3I2(g)
2DyI3(s)
Reactions with acids
Dysprosium dissolves readily in dilute sulphuric acid to form solutions containing the
yellow aquated Dy(III) ion together with hydrogen gas.
2Dy(s) + 3H2SO4(aq)
2Dy3+(aq) + 3SO42-(aq) + 3H2(g)
Holmium [Ho]
CAS-ID: 7440-60-0
An: 67 N: 98
Am: 164.93032 g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 2993K (2720°C)
Melting Point: 1734K (1461°C)
Density: 8.79g/cm3
Discovery Information
Who: J.L. Soret
When: 1878
Where: Switzerland
Name Origin
From Holmia, the Latin name for Stockholm.
"Holmium" in different languages.
Sources
Occurs in gadolinite, monazie and other rare-earth minerals. Annual production is
around 10 tons.
Abundance
Universe: 0.0005 ppm (by weight)
Carbonaceous meteorite: 0.06 ppm
Earth's Crust: 1.4 ppm
Seawater:
Atlantic surface: 2.4 x 10-7 ppm
Atlantic deep: 2.9 x 10-7 ppm
Pacific surface: 1.6 x 10-7 ppm
Pacific deep: 1.6 x 10-7 ppm
Uses
As control-rods for nuclear reactors because it readily absorbs neutrons. Forms highly
magnetic compounds when combined with yttrium. Holmium oxide is used as a yellow
glass colouring.
Its very high magnetic moment is suitable for use in yttrium-iron-garnet (YIG) and
yttrium-lanthanum-fluoride (YLF) solid state lasers found in microwave equipment
(which are in turn found in a variety of medical and dental settings).
History
Holmium (Holmia, Latin name for Stockholm) was discovered by Marc Delafontaine and
Jacques-Louis Soret in 1878 who noticed the aberrant spectrographic absorption bands
of the then-unknown element (they called it "Element X"). Later in 1878, Per Teodor
Cleve independently discovered the element while he was working on erbia earth
(erbium oxide).
Using the method developed by Carl Gustaf Mosander, Cleve first removed all of the
known contaminants from erbia. The result of that effort was two new materials, one
brown and one green. He named the brown substance holmia (after the Latin name for
Cleve's home town, Stockholm) and the green one thulia. Holmia was later found to be
the holmium oxide and thulia was thulium oxide.
Notes
The element, as with other rare earth elements, appears to have a low acute toxic
rating. Holmium plays no biological role in humans but may be able to stimulate
metabolism.
Isotopes of Holmium
Notable Isotopes
165
Ho [98 neutrons]
Abundance: 100%
Stable with 98 neutrons
Erbium [Er]
CAS-ID: 7440-52-0
An: 68 N: 99
Am: 167.259 (3) g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 3141K (2868°C)
Melting Point: 1770K (1497°C)
Density: 9.066g/cm3
Discovery Information
Who: Carl Mosander
When: 1843
Where: Sweden
Name Origin
From Ytterby, Sweden.
"Erbium" in different languages.
Sources
Found with other heavier rare earth metals, and in the minerals xenotime and euxenite
((Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6). Around 500 tons are produced annually.
Primary mining locations are in the USA, Brazil, India, Sri Lanka and Australia.
Abundance
Universe: 0.002 ppm (by weight)
Sun: 0.001 ppm (by weight)
Carbonaceous meteorite: 0.18 ppm
Earth's Crust: 3.8 ppm
Seawater:
Atlantic surface: 5.9 x 10-7 ppm
Atlantic deep: 8.6 x 10-7 ppm
Pacific surface: n/a ppm
Pacific deep: n/a ppm
Uses
For making photographic filters and as a neutron absorber. Erbium oxide is used in
ceramics to obtain a pink glaze.
When added to vanadium as an alloy erbium lowers hardness and improves
workability.
History
Erbium (for Ytterby, a town in Sweden) was discovered by Carl Gustaf Mosander in
1843. Mosander separated "yttria" from the mineral gadolinite
((Ce,La,Nd,Y)2FeBe2Si2O10) into three fractions which he called yttria, erbia, and terbia.
He named the new element after the town of Ytterby where large concentrations of
yttria and erbium are located. Erbia and terbia, however, were confused at this time.
After 1860, terbia was renamed erbia and after 1877 what had been known as erbia
was renamed terbia. Fairly pure Er2O3 was independently isolated in 1905 by Georges
Urbain and Charles James. Reasonably pure metal wasn't produced until 1934 when
workers reduced the anhydrous chloride with potassium vapour.
Notes
A trivalent element, pure erbium metal is malleable, soft yet stable in air and does not
oxidize as quickly as some other rare-earth metals. Its salts are rose-coloured and the
element gives a characteristic sharp absorption spectra in visible light, ultraviolet, and
near infrared. Otherwise it looks much like the other rare earths.
Hazards
Metallic erbium in dust form presents a fire and explosion hazard.
Erbium is mostly dangerous in the working environment, due to the fact that damps
and gasses can be inhaled with air. This can cause lung embolisms, especially during
long-term exposure. Erbium can be a threat to the liver when it accumulates in the
human body.
Isotopes of Erbium
Notable Isotopes
160
Er [92 neutrons]
Abundance: synthetic
Half life: 28.58 hours [ Electron Capture ]
Decay Energy: 0.330MeV
Decays to
162
160
Ho.
Er [94 neutrons]
Abundance: 0.14%
Stable with 94 neutrons
164
Er [96 neutrons]
Abundance: 1.61%
Stable with 96 neutrons
165
Er [97 neutrons]
Abundance: synthetic
Half life: 10.36 hours [ Electron Capture ]
Decay Energy: 0.376MeV
Decays to
166
165
Ho.
Er [98 neutrons]
Abundance: 33.6%
Stable with 98 neutrons
167
Er [99 neutrons]
Abundance: 22.95%
Stable with 99 neutrons
168
Er [100 neutrons]
Abundance: 26.8%
Stable with 100 neutrons
169
Er [101 neutrons]
Abundance: synthetic
Half life: 9.4 days [ beta- ]
Decay Energy: 0.351MeV
Decays to
170
169
Tm.
Er [102 neutrons]
Abundance: 14.9%
Stable with 102 neutrons
171
Er [103 neutrons]
Abundance: synthetic
Half life: 7.516 hours [ beta- ]
Decay Energy: 1.490MeV
Decays to
172
171
Tm.
Er [104 neutrons]
Abundance: synthetic
Half life: 49.3 hours [ beta- ]
Decay Energy: 0.891MeV
Decays to
172
Tm.
Reactions of Erbium
Reactions with water
The erbium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form erbium hydroxide and hydrogen gas.
2Er(s) + 6H2O(g)
2Er(OH)3(aq) + 3H2(g)
Reactions with air
Erbium tarnishes slowly in air and burns readily to form erbium (III) oxide.
4Er(s) + 3O2(g)
2Er2O3(s)
Reactions with halogens
Erbium reacts with all the halogens to form erbium(III) halides.
2Er(s) + 3F2(g)
2ErF3(s)
2Er(s) + 3Cl2(g)
2ErCl3(s)
2Er(s) + 3Br2(g)
2ErBr3(s)
2Er(s) + 3I2(g)
2ErI3(s)
Reactions with acids
Erbium dissolves readily in dilute sulphuric acid to form solutions containing the yellow
aquated Er(III) ion together with hydrogen gas.
2Er(s) + 3H2SO4(aq)
2Er3+(aq) + 3SO42-(aq) + 3H2(g)
Thulium [Tm]
CAS-ID: 7440-30-4
An: 69 N: 100
Am: 168.93421 g/mol
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 2223K (1950°C)
Melting Point: 1818K (1545°C)
Density: 9.32g/cm3
Discovery Information
Who: Per Theodor Cleve
When: 1879
Where: Sweden
Name Origin
From Thule ancient name of Scandinavia.
"Thulium" in different languages.
Sources
Found with other rare earths in the minerals; monazite, gadolinite, euxenite
((Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6), xenotime, and others.
Primary producers are the USA, Brazil, India, Sri Lanka and Australia. Annual
production is around 50 tons.
Abundance
Universe: 0.0001 ppm (by weight)
Sun: 0.0002 ppm (by weight)
Carbonaceous meteorite: 0.03 ppm
Earth's Crust: 0.48 ppm
Seawater:
Atlantic surface: 1.3 x 10-7 ppm
Atlantic deep: 1.6 x 10-7 ppm
Pacific surface: 7 x 10-8 ppm
Pacific deep: 3.3 x 10-7 ppm
Uses
None of thulium's compounds is commercially important mainly due to high production
costs. Radioactive thulium is used to power portable x-ray machines, eliminating the
need for electrical equipment.
Thulium-doped calcium sulphate (CaSO4) has been used in personal radiation
dosimeters because it can register, by its fluorescence, especially low levels.
History
Thulium was discovered by Swedish chemist Per Teodor Cleve in 1879 by looking for
impurities in the oxides of other rare earth elements (this was the same method Carl
Gustaf Mosander earlier used to discover some other rare earth elements). Cleve
started by removing all of the known contaminants of erbia (Er2O3) and upon additional
processing, obtained two new substances; one brown and one green. The brown
substance turned out to be the oxide of the element holmium and was named holmia
by Cleve and the green substance was the oxide of an unknown element. Cleve named
the oxide thulia and its element thulium after Thule, Scandinavia.
Thulium was so rare, that none of the early workers had enough of it to purify
sufficiently to actually see the green colour; they had to be content with observing the
strengthening of the two characteristic absorption bands, as erbium was progressively
removed. The first researcher to obtain thulium nearly pure was the British expatriate
working on a large scale at New Hampshire College in Durham NH: Charles James. In
1911, he reported his results, having used his discovered method of bromate fractional
crystallization to do the purification. He famously needed 15,000 "operations" to
establish that the material was homogeneous.
Notes
Thulium is the least abundant of the rare earth metals, is is and easy metal to work as
it can be cut by a knife. Reserves of thulium are estimated to be about 10 5 tonnes.
World production is about 50 tonnes per year as thulium oxide.
Hazards
Thulium has a low-to-moderate acute toxic rating and should be handled with care.
Metallic thulium in dust form presents a fire and explosion hazard.
Isotopes of Thulium
Notable Isotopes
167
Tm [98 neutrons]
Abundance: synthetic
Half life: 9.25 days [ Electron Capture ]
Decay Energy: 0.748MeV
Decays to
168
167
Er.
Tm [99 neutrons]
Abundance: synthetic
Half life: 93.1 days [ Electron Capture ]
Decay Energy: 1.679MeV
Decays to
169
168
Er.
Tm [100 neutrons]
Abundance: 100%
Stable with 100 neutrons
170
Tm [101 neutrons]
Abundance: synthetic
Half life: 128.6 days [ beta- ]
Decay Energy: 0.968MeV
Decays to
171
170
Yb.
Tm [102 neutrons]
Abundance: synthetic
Half life: 1.92 years [ beta- ]
Decay Energy: 0.96MeV
Decays to
171
Yb.
Reactions of Thulium
Reactions with water
The silvery white metal thulium is quite electropositive and reacts slowly with cold
water and quite quickly with hot water to form thulium hydroxide and hydrogen gas.
2Tm(s) + 6H2O(g)
2Tm(OH)3(aq) + 3H2(g)
Reactions with air
Thulium tarnishes slowly in air and burns readily to form thulium (III) oxide.
4Tm(s) + 3O2(g)
2Tm2O3(s)
Reactions with halogens
Thulium reacts with all the halogens to form thulium(III) halides.
2Tm(s) + 3F2(g)
2TmF3(s)
2Tm(s) + 3Cl2(g)
2TmCl3(s)
2Tm(s) + 3Br2(g)
2TmBr3(s)
2Tm(s) + 3I2(g)
2TmI3(s)
Reactions with acids
Thulium dissolves readily in dilute sulphuric acid to form solutions containing the pale
green aquated Tm(III) ion together with hydrogen gas.
2Tm(s) + 3H2SO4(aq)
Ytterbium [Yb]
CAS-ID: 7440-64-4
An: 70 N: 103
Am: 173.04 (3) g/mol
2Tm3+(aq) + 3SO42-(aq) + 3H2(g)
Group Name: Lanthanoids
Block: f-block Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 1469K (1196°C)
Melting Point: 1097K (824°C)
Density: 6.90g/cm3
Discovery Information
Who: Jean de Marignac
When: 1878
Where: Switzerland
Name Origin
From Ytterby, Sweden.
"Ytterbium" in different languages.
Sources
Found in minerals such as yttria, monazite, gadolinite, and xenotime. Natural
ytterbium is a mix of seven stable isotopes.
Important producers are the USA, Canada, Greenland and Brazil. Annual production is
around 50 tons.
Abundance
Universe: 0.002 ppm (by weight)
Sun: 0.001 ppm (by weight)
Carbonaceous meteorite: 0.18 ppm
Earth's Crust: 3.3 ppm
Seawater:
Atlantic surface: 5 x 10-7 ppm
Atlantic deep: 7.5 x 10-7 ppm
Pacific surface: 3.7 x 10-7 ppm
Pacific deep: 2.2 x 10-6 ppm
Uses
Used in metallurgical and chemical experiments.
One ytterbium isotope has been used as a radiation source substitute for a portable Xray machine when electricity was not available.
Ytterbium has a single absorption band at 985 nanometers, which is used to convert
infrared energy into electricity in solar cells.
History
Ytterbium was discovered by the Swiss chemist Jean Charles Galissard de Marignac in
1878. Marignac found a new component in the earth then known as erbia and named it
ytterbia (after Ytterby, the Swedish town where he found the new erbia component).
He suspected that ytterbia was a compound of a new element he called ytterbium.
In 1907, the French chemist Georges Urbain separated Marignac's ytterbia into two
components, neoytterbia and lutecia. Neoytterbia would later become known as the
element ytterbium and lutecia would later be known as the element lutetium. Auer von
Welsbach independently isolated these elements from ytterbia at about the same time
but called them aldebaranium and cassiopeium.
Notes
The chemical and physical properties of ytterbium could not be determined until 1953
when the first nearly pure ytterbium was produced
Hazards
Although it was thought that all ytterbium compounds were highly toxic, initial studies
have shown that the danger is limited. Ytterbium compounds are known to cause skin
and eye irritations, and may also be teratogenic. Metallic ytterbium dust poses a fire
and explosion hazard.
Isotopes of Ytterbium
Notable Isotopes
166
Yb [96 neutrons]
Abundance: synthetic
Half life: 56.7 hours [ Electron Capture ]
Decay Energy: 0.304MeV
Decays to
168
166
Tm.
Yb [98 neutrons]
Abundance: 0.13%
Stable with 98 neutrons
169
Yb [99 neutrons]
Abundance: synthetic
Half life: 32.026 days [ Electron Capture ]
Decay Energy: 0.909MeV
Decays to
170
169
Tm.
Yb [100 neutrons]
Abundance: 3.05%
Stable with 100 neutrons
171
Yb [101 neutrons]
Abundance: 14.3%
Stable with 101 neutrons
172
Yb [102 neutrons]
Abundance: 21.9%
Stable with 102 neutrons
173
Yb [103 neutrons]
Abundance: 16.12%
Stable with 103 neutrons
174
Yb [104 neutrons]
Abundance: 31.8%
Stable with 104 neutrons
175
Yb [105 neutrons]
Abundance: synthetic
Half life: 4.185 days [ beta- ]
Decay Energy: 0.470MeV
Decays to
176
175
Lu.
Yb [106 neutrons]
Abundance: 12.7%
Stable with 106 neutrons
177
Yb [107 neutrons]
Abundance: synthetic
Half life: 1.911 hours [ beta- ]
Decay Energy: 1.399MeV
Decays to
177
Lu.
Reactions of Ytterbium
Reactions with water
Ytterbium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form ytterbium hydroxide and hydrogen gas.
2Yb(s) + 6H2O(g)
2Yb(OH)3(aq) + 3H2(g)
Reactions with air
Ytterbium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form ytterbium hydroxide and hydrogen gas.
4Yb + 3O2
2Yb2O3
Reactions with halogens
Ytterbium metal reacts with all the halogens to form ytterbium(III) halides.
2Yb(s) + 3F2(g)
2YbF3(s)
2Yb(s) + 3Cl2(g)
2YbCl3(s)
2Yb(s) + 3Br2(g)
2YbBr3(s)
2Yb(s) + 3I2(g)
2YbI3(s)
Reactions with acids
Ytterbium metal dissolves readily in dilute sulphuric acid to form solutions containing
the colourless aquated Yb(III) ion together with hydrogen gas.
2Yb(s) + 3H2SO4(aq)
2Yb3+(aq) + 3SO42-(aq) + 3H2(g)>
Lutetium [Lu]
CAS-ID: 7439-94-3
An: 71 N: 104
Am: 174.967 (1) g/mol
Group No: 3
Group Name: Lanthanoids
Block: d-block Period: 6
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 3675K (3402°C)
Melting Point: 1925K (1652°C)
Superconducting temperature: 0.022K (-273.128°C)
Density: 9.841g/cm3
Discovery Information
Who: Georges Urbain
When: 1907
Where: France
Name Origin
From Lutetia the ancient name of Paris.
"Lutetium" in different languages.
Sources
Found with almost all other rare-earth metals but never by itself, lutetium is very
difficult to separate from other elements. Consequently, it is also one of the most
expensive metals, costing about six times as much as gold.
The principal commercially viable ore of lutetium is the rare earth phosphate mineral
monazite: (Ce, La, etc.)PO4 which contains 0.003% of the element. Pure lutetium
metal has only relatively recently been isolated and is very difficult to prepare (thus it
is one of the most rare and expensive of the rare earth metals).
Primary mining locations are the USA, Brazil, India, Sri Lanka, Australia and Chine.
Annual production is around 10 tons.
Abundance
Universe: 0.0001 ppm (by weight)
Sun: 0.001 ppm (by weight)
Carbonaceous meteorite: 0.03 ppm
Earth's Crust: 0.51 ppm
Seawater:
Atlantic surface: 1.4 x 10-7 ppm
Atlantic deep: 2 x 10-7 ppm
Pacific surface: 6 x 10-8 ppm
Pacific deep: 4.1 x 10-7 ppm
Uses
This element is very expensive to obtain in useful quantities and therefore it has very
few commercial uses. Used in alloys and can be used as a catalyst in cracking,
hydrogenation, polymerization and alkylation.
A tiny amount of lutetium is added as a dopant to gadolinium gallium garnet (GGG),
which is used in magnetic bubble memory devices.
History
Lutetium (Latin Lutetia meaning Paris) was independently discovered in 1907 by
French scientist Georges Urbain and Austrian mineralogist Baron Carl Auer von
Welsbach. Both men found lutetium as an impurity in the mineral ytterbia which was
thought by Swiss chemist Jean Charles Galissard de Marignac (and most others) to
consist entirely of the element ytterbium.
The separation of lutetium from Marignac's ytterbium was first described by Urbain and
the naming honor therefore went to him. He chose the names neoytterbium (new
ytterbium) and lutecium for the new element but neoytterbium was eventually
reverted back to ytterbium and in 1949 the spelling of element 71 was changed to
lutetium.
Welsbach proposed the names cassiopium for element 71 (after the constellation
Cassiopeia) and albebaranium for the new name of ytterbium but these naming
proposals where rejected (although many German scientists in the 1950s called the
element 71 cassiopium).
Notes
Because of the difficulty in producing pure lutetium it is one of the most expensive
metals, costing around six times as much per gram as gold.
Hazards
Like other rare-earth metals lutetium is regarded as having a low toxicity rating but it
and especially its compounds should be handled with care nonetheless. Metal dust of
this element is a fire and explosion hazard. Lutetium plays no biological role in the
human body but is thought to help stimulate metabolism.
Isotopes of Lutetium
Notable Isotopes
173
Lu [102 neutrons]
Abundance: synthetic
Half life: 1.37 years [ Electron Capture ]
Decay Energy: 0.671MeV
Decays to
174
173
Yb.
Lu [103 neutrons]
Abundance: synthetic
Half life: 3.31 years [ Electron Capture ]
Decay Energy: 1.374MeV
Decays to
175
174
Yb.
Lu [104 neutrons]
Abundance: 97.41%
Stable with 104 neutrons
176
Lu [105 neutrons]
Abundance: 2.59%
Half life: 3.78 x 1010 years [ beta- ]
Decay Energy: 1.193MeV
Decays to
176
Hf.
Reactions of Lutetium
Reactions with water
Lutetium is quite electropositive and reacts slowly with cold water and quite quickly
with hot water to form lutetium hydroxide and hydrogen gas.
2Lu(s) + 6H2O(g)
2Lu(OH)3(aq) + 3H2(g)
Reactions with air
Lutetium metal tarnishes slowly in air and burns readily to form lutetium (III) oxide.
4Lu + 3O2
2Lu2O3
Reactions with halogens
Lutetium metal reacts with all the halogens to form lutetium(III) halides.
2Lu(s) + 3F2(g)
2LuF3(s)
2Lu(s) + 3Cl2(g)
2LuCl3(s)
2Lu(s) + 3Br2(g)
2LuBr3(s)
2Lu(s) + 3I2(g)
2LuI3(s)
Reactions with acids
Lutetium dissolves readily in dilute sulphuric acid to form solutions containing the
colourless aquated Lu(III) ion together with hydrogen gas.
2Lu(s) + 3H2SO4(aq)
Thorium [Th]
CAS-ID: 7440-29-1
An: 90 N: 142
Am: 232.0381 g/mol
Group Name: Actinoid
2Lu3+(aq) + SO42-(aq) + 3H2(g)
Block: f-block Period: 7 (actinoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 5093K (4820°C)
Melting Point: 2115K (1842°C)
Superconducting temperature: 1.38K (-271.77°C)
Density: 11.7g/cm3
Discovery Information
Who: Jons Berzelius
When: 1828
Where: Sweden
Name Origin
From the Scandinavian god Thor.
"Thorium" in different languages.
Sources
Found in various minerals like monazite and thorite ((Th,U)SiO4). Thorium is found in
small amounts in most rocks and soils (about 6ppm), where it is three times more
abundant than uranium and about as common as lead.
Primary producers are the USA, Brazil, India, Sri Lanka, Madagascar, Russia and
Australia. Annual production is around 31 thousand tons.
Abundance
Universe: 0.0004 ppm (by weight)
Sun: 0.0003 ppm (by weight)
Carbonaceous meteorite: 0.04 ppm
Earth's Crust: 12 ppm
Seawater: 9.2 ppm
Uses
Used in making strong alloys, ultraviolet photoelectric cells, mantles in portable gas
lights and for coating tungsten wire in electronic equipment. Bombarded with neutrons
make uranium-233, a nuclear fuel.
Thorium dioxide (ThO2) is used in producing high-temperature laboratory crucibles.
When added to glass it helps create glasses of a high refractive index and with low
dispersion. Consequently, they find application in high-quality lenses for cameras and
scientific instruments.
History
M. T. Esmark found a black mineral on Lovoy Island, Norway and gave a sample to
Professor Jens Esmark, a noted mineralogist who was not able to identify it so he sent
a sample to the Swedish chemist Jons Jakob Berzelius for examination in 1828.
Berzelius analysed it and named it after Thor, the Norse god of thunder. The metal had
virtually no uses until the invention of the gas mantle in 1885.
The crystal bar process (or Iodide process) was discovered by Anton Eduard van Arkel
and Jan Hendrik de Boer in 1925 to produce high-purity metallic thorium.
The name ionium was given early in the study of radioactive elements to the 230Th
isotope produced in the decay chain of 238U before it was realized that ionium and
thorium were chemically identical. The symbol Io was used for this supposed element.
Notes
Thorium dioxide (ThO2), also called thoria, has one of the highest melting points of all
oxides (3300°C).
Isotopes of Thorium
Notes
Thorium has no stable isotopes.
Notable Isotopes
228
Th [138 neutrons]
Abundance: Synthetic
Half life: 1.9116 years [ Alpha Decay ]
Decay Energy: 5.520MeV
Decays to
229
Ra.
224
Th [139 neutrons]
Abundance: Synthetic
Half life: 7340 years [ Alpha Decay ]
Decay Energy: 5.168MeV
Decays to
230
Ra.
225
Th [140 neutrons]
Abundance: Synthetic
Half life: 75380 years [ Alpha Decay ]
Decay Energy: 4.770MeV
Decays to
232
Ra.
226
Th [142 neutrons]
Abundance: 100%
Half life: 1.4505 x 1010years [ Alpha Decay ]
Decay Energy: 4.083MeV
Decays to
Ra.
228
Protactinium [Pa]
CAS-ID: 7440-13-3
An: 91 N: 122
Am: 231.03588 g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid)
State: solid at 298 K
Colour: silvery metallic Classification: Metallic
Boiling Point: 4300K (4300°C)
Melting Point: 1841K (1568°C)
Superconducting temperature: 1.4K (-271.7°C)
Density: 15.37g/cm3
Discovery Information
Who: Fredrich Soddy, John Cranston, Otto Hahn, Lise Meitner
When: 1917
Where: England/France
Name Origin
protos (first); its is the parent of actinium, which is formed by radioactive decay.
"Protactinium" in different languages.
Sources
Does not occur in nature. Found among fission products of uranium, thorium, and
plutonium.
Protactinium occurs in pitchblende to the extent of about 1 part 231Pa to 10 million of
ore. Some ores from the Democratic Republic of the Congo have about 3 ppm.
Abundance
Earth's Crust: 1 x 10-8 ppm
Seawater: 2 x 10-11 ppm
Uses
Because of its scarcity, high radioactivity and toxicity, there are currently no uses for
protactinium outside of basic scientific research.
History
An element between thorium and uranium was predicted to exist by Mendeleev in
1871. In 1900 William Crookes isolated protactinium as a radioactive material from
uranium which he could not identify
Protactinium was first identified in 1913, when Kasimir Fajans and O. H. Gohring
encountered short-lived isotope 234m-Pa, with a half-life of about 1.17 minutes,
during their studies of the decay chain of 238-U. They gave the new element the name
Brevium (Latin brevis, brief, short); the name was changed to Protoactinium in 1918
when two groups of scientists (Otto Hahn and Lise Meitner of Germany and Frederick
Soddy and John Cranston of the UK) independently discovered 231-Pa, and shortened
to Protactinium in 1949.
Aristid V. Grosse prepared 2 mg of Pa2O5 in 1927, and later on managed to isolate
Protactinium for the first time in 1934 from 0.1 mg of Pa2O5, first converting the oxide
to an iodide and then cracking it in a high vacuum by an electrically heated filament.
In 1961, the United Kingdom Atomic Energy Authority was able to produce 125 g of
99.9% pure protactinium, processing 60 tons of waste material in a 12-stage process
and spending 500,000 USD; this was the world's only supply of the element for many
years to come, and it is reported that the metal was sold to laboratories for a cost of
2,800 USD / g in the following years.
Notes
It is superconductive at temperatures below 1.4 K (-271.74°C).
29 radioisotopes of protactinium have been characterized, with the most stable being
231
Pa with a half life of 32760 years, 233Pa with a half-life of 26.967 days, and 230Pa
with a half-life of 17.4 days. All of the remaining radioactive isotopes have half-lives
that are less than 1.6 days, and the majority of these have half lifes that are less than
1.8 seconds.
Hazards
Protactinium is both toxic and highly radioactive.
Isotopes of Protactinium
Notes
Protactinium has no stable isotopes.
Notable Isotopes
230
Pa [139 neutrons]
Abundance: synthetic
Half life: 17.4 days [ Electron Capture ]
Decay Energy: 1.310MeV
Decays to
230
Th.
Half life: 17.4 days [ beta- ]
Decay Energy: 0.563MeV
Decays to
231
U.
230
Pa [140 neutrons]
Abundance: synthetic
Half life: 32760 years [ Alpha Decay ]
Decay Energy: 5.149MeV
Decays to
233
Ac.
227
Pa [142 neutrons]
Abundance: synthetic
Half life: 26.967 days [ beta- ]
Decay Energy: 0.571MeV
Decays to
U.
233
Uranium [U]
CAS-ID: 7440-61-1
An: 92 N: 146
Am: 238.02891 (3) g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid)
State: solid at 298 K
Colour: metallic grey Classification: Metallic
Boiling Point: 4200K (3927°C)
Melting Point: 1405.3K (1132.2°C)
Superconducting temperature: 0.2K (-272.9°C)
Density: 19.1g/cm3
Discovery Information
Who: Martin Klaproth
When: 1789
Where: Germany
Name Origin
From planet Uranus.
"Uranium" in different languages.
Sources
Occurs in many rocks, but in large amounts only in such minerals as pitchblende and
carnotite (K2(UO2)2(VO4)2 - 3H2O). Annual production is around 35 thousand tons.
Abundance
Universe: 0.0002 ppm (by weight)
Sun: 0.001 ppm (by weight)
Carbonaceous meteorite: 0.010 ppm
Earth's Crust: 1.8 ppm
Seawater: 3.13 x 10-3 ppm
Human:
1 ppb by weight
0.03 ppb by atoms
Uses
For many centuries it was used as a pigment for glass. Now it is used as a fuel in
nuclear reactors and in nuclear bombs. Depleted Uranium ( 238U) is used in casings of
armour piercing artillery shells, armour plating on tanks and as ballast in the wings of
some large aircraft.
History
The use of uranium in its natural oxide form dates back to at least the year AD79,
when it was used to add a yellow colour to ceramic glazes. Yellow glass with 1%
uranium oxide was found in a Roman villa on Cape Posillipo in the Bay of Naples, Italy
by R. T. Gunther of the University of Oxford in 1912. Starting in the late Middle Ages,
pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia
(now Jachymov in the Czech Republic) and was used as a colouring agent in the local
glassmaking industry. In the early 19th century, the world's only known source of
uranium ores were these old mines.
The discovery of the element is credited to the German chemist Martin Heinrich
Klaproth. While he was working in his experimental laboratory in Berlin in 1789,
Klaproth was able to precipitate a yellow compound (likely sodium diuranate) by
dissolving pitchblende in nitric acid and neutralizing the solution with sodium
hydroxide. Klaproth mistakenly assumed the yellow substance was the oxide of a yetundiscovered element and heated it with charcoal to obtain a black powder, which he
thought was the newly discovered metal itself (in fact, that powder was an oxide of
uranium). He named the newly discovered element after the planet Uranus, which had
been discovered eight years earlier by William Herschel.
In 1841, Eugene-Melchior Peligot, who was Professor of Analytical Chemistry at the
Conservatoire des arts et metiers (Central School of Arts and Manufactures) in Paris,
isolated the first sample of uranium metal by heating uranium tetrachloride with
potassium. Uranium was not seen as being particularly dangerous during much of the
19th century, leading to the development of various uses for the element. One such
use for the oxide was the aforementioned but no longer secret colouring of pottery and
glass.
Antoine Becquerel discovered radioactivity by using uranium in 1896. Becquerel made
the discovery in Paris by leaving a sample of uranium on top of an unexposed
photographic plate in a drawer and noting that the plate had become 'fogged'. He
determined that a form of invisible light or rays emitted by uranium had exposed the
plate.
Notes
Uranium metal has very high density, 65% more dense than lead, but slightly less
dense than gold.
70% of the world's known Uranium is located in Australia. The Australian government
is currently advocating an expansion of uranium mining, although issues with state
governments and indigenous interests complicate the issue.
Hazards
Potential occupational carcinogen (lung cancer). All isotopes and compounds of
uranium are very toxic, teratogenic and radioactive. Finely-divided uranium metal
presents a fire hazard because uranium is pyrophoric, so small grains will ignite
spontaneously in air at room temperature.
Isotopes of Uranium
Notes
Uranium has no stable isotopes.
Notable Isotopes
U [140 neutrons]
232
Abundance: synthetic
Half life: 68.9 years
Decay Energy: 5.414MeV
Decays to
228
Th.
U [141 neutrons]
233
Abundance: synthetic
Half life: 159200 years
Decay Energy: 4.909MeV
Decays to
229
Th.
U [142 neutrons]
234
Abundance: 0.006%
Half life: 245500 years
Decay Energy: 4.859MeV
Decays to
230
Th.
U [143 neutrons]
235
Abundance: 0.72%
Half life: 7.038 x 108 years
Decay Energy: 4.679MeV
Decays to
231
Th.
U is unique in its ability to cause a rapidly expanding fission chain reaction, i.e., it is fissile. In
fact, U-235 is the only fissile isotope found in nature. It was discovered in 1935 by Arthur Jeffrey
Dempster. A uranium nucleus that absorbs a neutron splits into two lighter nuclei; this is called
nuclear fission. It releases either two or three neutrons which continue the reaction. In nuclear
reactors, the reaction is slowed down by the addition of control rods which are made of elements
such as boron, cadmium, and hafnium which can absorb a large number of neutrons. In nuclear
bombs, the reaction is uncontrolled and the large amount of energy released creates a nuclear
explosion.
235
U [144 neutrons]
236
Abundance: synthetic
Half life: 2.342 x 107 years
Decay Energy: 4.572MeV
Decays to
232
Th.
U [146 neutrons]
238
Abundance: 99.275%
Half life: 4.468 x 109 years
Decay Energy: 4.260MeV
Decays to
234
Th.
Neptunium [Np]
CAS-ID: 7439-99-8
An: 93 N: 144
Am: [237] g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid)
State: solid at 298 K
Colour: silvery metallic Classification: Metallic
Boiling Point: 4273K (4000°C)
Melting Point: 910K (637°C)
Density: 20.2g/cm3
Discovery Information
Who: E.M. McMillan, P.H. Abelson
When: 1940
Where: United States
Name Origin
From planet Neptune.
"Neptunium" in different languages.
Sources
Produced by bombarding uranium with slow neutrons. Neptunium is also found in trace
amounts in uranium ores.
Its most stable isotope, 237Np, is a by-product of nuclear reactors and plutonium
production and it can be used as a component in neutron detection equipment.
Uses
Used in neutron detection instruments.
Np is irradiated with neutrons to create
spacecraft and military applications.
237
Pu, a rare and valuable isotope for
238
History
Neptunium (named for the planet Neptune, the next planet out from Uranus, after
which uranium was named) was first discovered by Edwin McMillan and Philip H.
Abelson in 1940. Initially predicted by Walter Russell's "spiral" organization of the
periodic table, it was found at the Berkeley Radiation Laboratory of the University of
California, Berkeley where the team produced the neptunium isotope 239Np (2.4 day
half-life) by bombarding uranium with slow moving neutrons. It was the first
transuranium element produced synthetically and the first actinoids series
transuranium element discovered.
Notes
It was the first transuranium element produced synthetically and the first actinoid
series transuranium element discovered.
19 neptunium radioisotopes have been characterized, with the most stable being 237Np
with a half-life of 2.14 million years, 236Np with a half-life of 154,000 years, and 235Np
with a half-life of 396.1 days. All of the remaining radioactive isotopes have half-lives
that are less than 4.5 days, and the majority of these have half-lives that are less than
50 minutes.
Isotopes of Neptunium
Notes
Neptunium has no stable isotopes.
Notable Isotopes
235
Np [142 neutrons]
Abundance: synthetic
Half life: 396.1 days [ Alpha Decay ]
Decay Energy: 5.192MeV
Decays to
231
Pa.
Half life: 396.1 days [ Electron Capture ]
Decay Energy: 0.124MeV
Decays to
236
U.
235
Np [143 neutrons]
Abundance: synthetic
Half life: 154 x 103 years [ Electron Capture ]
Decay Energy: 0.940MeV
Decays to
U.
236
Half life: 154 x 103 years [ beta- ]
Decay Energy: 0.940MeV
Decays to
236
Pu.
Half life: 154 x 103 years [ Alpha Decay ]
Decay Energy: 5.020MeV
Decays to
237
232
Pa.
Np [144 neutrons]
Abundance: synthetic
Half life: 2.144 x 106 years
Decay Energy: 4.959MeV
Decays to
232
Pa.
Plutonium [Pu]
CAS-ID: 7440-07-5
An: 94 N: 150
Am: [244] g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 3503K (3230°C)
Melting Point: 912.5K (639.4°C)
Density: 19.816g/cm3
Discovery Information
Who: G.T.Seaborg, J.W.Kennedy, E.M.McMillan, A.C.Wahl
When: 1940
Where: United States
Name Origin
From planet Pluto.
"Plutonium" in different languages.
Sources
Almost all plutonium is manufactured synthetically, extremely tiny trace amounts are
found naturally in uranium ores. Most plutonium is made synthetically by bombarding
uranium with neutrons.
Annual production is around 20 tons, it is thought that world reserves are around 500
tons.
Uses
Used in bombs and reactors. Complete detonation of plutonium will produce an
explosion equivalent to 20 kilotons of Trinitrotoluene (TNT) per kilogram (of
plutonium).
History
The production of plutonium and neptunium by bombarding uranium-238 with
neutrons was predicted in 1940 by two teams working independently: Edwin M.
McMillan and Philip Abelson at Berkeley Radiation Laboratory at the University of
California, Berkeley and by Egon Bretscher and Norman Feather at the Cavendish
Laboratory at University of Cambridge. Coincidentally both teams proposed the same
names to follow on from uranium, like the sequence of the outer planets.
Plutonium was first produced and isolated on February 23, 1941 by Dr. Glenn T.
Seaborg, Dr. Michael Cefola, Edwin M. McMillan, J. W. Kennedy, and A. C. Wahl by
deuteron bombardment of uranium in the 60-inch cyclotron at Berkeley. The discovery
was kept secret due to the war. It was named after Pluto, having been discovered
directly after neptunium (which itself was one higher on the periodic table than
uranium), by analogy to solar system planet order as Pluto was considered to be a
planet at the time (though technically it should have been "plutium", Seaborg said that
he did not think it sounded as good as "plutonium"). Seaborg chose the letters "Pu" as
a joke, which passed without notice into the periodic table. Originally, Seaborg and
others thought about naming the element "ultinium" or "extremium" because they
believed at the time that they had found the last possible element on the periodic
table.
Chemists at the University of Chicago began to study the newly manufactured
radioactive element. The George Herbert Jones Laboratory at the university was the
site where, for the first time, a trace quantity of this new element was isolated and
measured in September 1942. This procedure enabled chemists to determine the new
element's atomic weight. Room 405 of the building was named a National Historic
Landmark in May 1967. During the Manhattan Project, the first production reactor was
built at the Oak Ridge, Tennessee site that later became Oak Ridge National
Laboratory. Later, large reactors were set up in Hanford, Washington, for the
production of plutonium, which was used in the first atomic bomb used at the "Trinity"
test at White Sands, New Mexico in July 1945. Plutonium was also used in the "Fat
Man" bomb dropped on Nagasaki, Japan in August 1945. The "Little Boy" bomb
dropped on Hiroshima utilized uranium-235, not plutonium.
During the initial years after the discovery of plutonium, when its biological and
physical properties were very poorly understood, a series of human radiation
experiments were performed by the U.S. government and by private organizations
acting on its behalf. During and after the end of World War II, scientists working on the
Manhattan Project and other nuclear weapons research projects conducted studies of
the effects of plutonium on laboratory animals and human subjects. In the case of
human subjects, this involved injecting solutions containing (typically) five micrograms
of plutonium into hospital patients thought to be either terminally ill, or to have a life
expectancy of less than ten years either due to age or chronic disease condition. These
eighteen injections were made without the informed consent of those patients and
were not done with the belief that the injections would heal their conditions; rather,
they were used to develop diagnostic tools for determining the uptake of plutonium in
the body for use in developing safety standards for people working with plutonium
during the course of developing nuclear weapons.
Notes
The heat given off by alpha particle emission makes plutonium warm to the touch in
reasonable quantities; larger amounts can boil water.
All isotopes and compounds of plutonium are toxic and radioactive.
Hazards
Plutonium is radioactive. When taken in by mouth, plutonium is less poisonous (except
for risk of causing cancer) than several common substances including caffeine,
acetaminophen, some vitamins, pseudoephedrine, and any number of plants and fungi.
It is perhaps somewhat more poisonous than pure ethanol (C 2H5OH), but less so than
tobacco; and many illegal drugs. From a purely chemical standpoint, it is about as
poisonous as lead and other heavy metals.
Isotopes of Plutonium
Notes
Plutonium has no stable isotopes.
Notable Isotopes
238
Pu [144 neutrons]
Abundance: synthetic
Half life: 88 years
Decay Energy: ?MeV
Decays to ?.
Half life: 88 years [ Alpha Decay ]
Decay Energy: 5.5MeV
Decays to
239
U.
234
Pu [145 neutrons]
Abundance: trace
Half life: 24.1 x 103 years
Decay Energy: ?MeV
Decays to ?.
Half life: 24.1 x 103 years [ Alpha Decay ]
Decay Energy: 5.245MeV
Decays to
240
U.
235
Pu [146 neutrons]
Abundance: synthetic
Half life: 6.5 x 103 years
Decay Energy: ?MeV
Decays to ?.
Half life: 6.5 x 103 years
Decay Energy: 0.005MeV
Decays to
241
Am.
240
Pu [147 neutrons]
Abundance: synthetic
Half life: 14 years [ Alpha Decay ]
Decay Energy: 4.9MeV
Decays to
U.
237
Half life: 14 years
Decay Energy: ?MeV
242
Pu [148 neutrons]
Abundance: synthetic
Half life: 3.73x 105 years
Decay Energy: ?MeV
Decays to ?.
Half life: 3.73x 105 years [ Alpha Decay ]
Decay Energy: 4.984MeV
Decays to
244
U.
238
Pu [150 neutrons]
Abundance: synthetic
Half life: 8.08 x 107 years [ Alpha Decay ]
Decay Energy: 4.66MeV
Decays to
U.
240
Half life: 8.08 x 107 years
Decay Energy: ?MeV
Decays to ?.
Americium [Am]
CAS-ID: 7440-35-9
An: 95 N: 148
Am: [243] g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 2880K (2607°C)
Melting Point: 1449K (1176°C)
Superconducting temperature: 0.6K (-272.5°C)
Density: 12g/cm3
Discovery Information
Who: G. T. Seaborg, R. A. James, L. O. Morgan, A. Ghiorso
When: 1945
Where: United States
Name Origin
From America by analogy with europium.
"Americium" in different languages.
Sources
Produced by bombarding plutonium with neutrons.
Uses
Americium-241 is currently used in smoke detectors.
The element has also been employed to gauge glass thickness to help create flat glass.
History
Americium was first isolated by Glenn T. Seaborg, Leon O. Morgan, Ralph A. James,
and Albert Ghiorso in late 1944 at the wartime Metallurgical Laboratory at the
University of Chicago (now known as Argonne National Laboratory). The team created
the isotope 241Am by subjecting 239Pu to successive neutron capture reactions in a
nuclear reactor. This created 240Pu and then 241Pu which in turn decayed into 241Am via
beta decay.
The discovery of americium and curium was first announced informally on a children's
quiz show in 1945.
Notes
Pure americium has a silvery and white lustre. At room temperatures it slowly
tarnishes in dry air. It is more silvery than plutonium or neptunium and apparently
more malleable than neptunium or uranium. Alpha emission from 241Am is
approximately three times that of radium.
18 radioisotopes of americium have been characterized, with the most stable being
243
Am with a half-life of 7370 years, and 241Am with a half-life of 432.2 years. All of the
remaining radioactive isotopes have half-lives that are less than 51 hours, and the
majority of these have half-lives that are less than 100 minutes.
Hazards
Americium is radioactive. Alpha emission from 241Am is approximately three times that
of radium. Gram quantities of 241Am emit intense gamma rays which creates a serious
exposure problem for anyone handling the element.
Isotopes of Americium
Notable Isotopes
Am [146 neutrons]
241
Abundance: synthetic
Half life: 432.2 years
Decay Energy: ?MeV
Decays to ?.
Half life: 432.2 years [ Alpha Decay ]
Decay Energy: 5.638MeV
Decays to
242m
237
Np.
Am [147 neutrons]
Abundance: synthetic
Half life: 141 years
Decay Energy: 0.049MeV
Decays to ?.
Half life: 141 years [ Alpha Decay ]
Decay Energy: 5.637MeV
Decays to
238
Np.
Half life: 141 years
Decay Energy: ?MeV
Decays to ?.
Am [148 neutrons]
243
Abundance: synthetic
Half life: 7370 years
Decay Energy: ?MeV
Decays to ?.
Half life: 7370 years [ Alpha Decay ]
Decay Energy: 5.438MeV
Decays to
239
Np.
Curium [Cm]
CAS-ID: 7440-51-9
An: 96 N: 151
Am: [247] g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid)
State: solid at 298 K
Colour: silver Classification: Metallic
Boiling Point: 3383K (3110°C)
Melting Point: 1613K (1340°C)
Density: 13.51g/cm3
Discovery Information
Who: G.T.Seaborg, R.A.James, A. Ghiorso
When: 1944
Where: United States
Name Origin
In honour of Pierre and Marie Curie.
"Curium" in different languages.
Sources
Made by bombarding plutonium with helium ions. Curium was made in elemental form
for the first time in 1951.
Uses
As curium is only available in extremely limited quantities, it has few uses, however, it
was used on a Mars mission as an alpha particle source for the Alpha Proton X-Ray
Spectrometer.
History
Curium was first synthesized at the University of California, Berkeley by Glenn T.
Seaborg, Ralph A. James, and Albert Ghiorso in 1944. The team named the new
element after Marie Curie and her husband Pierre who are famous for discovering
radium and for their work in radioactivity. It was chemically identified at the
Metallurgical Laboratory (now Argonne National Laboratory) at the University of
Chicago. It was actually the third transuranium element to be discovered even though
it is the second in the series. Curium-242 (half-life 163 days) and one free neutron
were made by bombarding alpha particles onto a plutonium-239 target in the 60-inch
cyclotron at Berkeley. Louis Werner and Isadore Perlman created a visible sample of
curium-242 hydroxide at the University of California in 1947 by bombarding
americium-241 with neutrons. Curium was made in its elemental form in 1951 for the
first time.
Notes
The isotope curium-248 has been synthesized only in milligram quantities, but curium242 and curium-244 are made in multigram amounts, which allows for the
determination of some of the element's properties.
Curium-242 can generate up to 120 watts of thermal energy per gram (W/g); its very
short half-life though makes it undesirable as a power source for long-term use.
19 radioisotopes of curium have been characterized, with the most stable being Cm247 with a half-life of 1.56 x 107 years, Cm-248 with a half-life of 3.40 x 105 years,
Cm-250 with a half-life of 9000 years, and Cm-245 with a half-life of 8500 years. All of
the remaining radioactive isotopes have half-lifes that are less than 30 years, and the
majority of these have half lifes that are less than 33 days.
So radioactive it glows in the dark.
Hazards
Curium bio-accumulates in bone tissue where its radiation destroys bone marrow and
thus stops red blood cell creation.
Isotopes of Curium
Notes
Curium has no stable isotopes.
Notable Isotopes
242
Cm [146 neutrons]
Abundance: synthetic
Half life: 160 days
Decay Energy: ?MeV
Half life: 160 days [ Alpha Decay ]
Decay Energy: 6.1MeV
Decays to
243
238
Pu.
Cm [147 neutrons]
Abundance: synthetic
Half life: 29.1 years [ Alpha Decay ]
Decay Energy: 6.169MeV
Decays to
239
Pu.
Half life: 29.1 years [ Electron Capture ]
Decay Energy: 0.009?MeV
Decays to
244
Am?.
243
Cm [148 neutrons]
Abundance: synthetic
Half life: 18.1 years
Decay Energy: ?MeV
Decays to ?.
Half life: 18.1 years [ Alpha Decay ]
Decay Energy: 5.902MeV
Decays to
245
240
Pu.
Cm [149 neutrons]
Abundance: synthetic
Half life: 8500 years
Decay Energy: ?MeV
Decays to ?.
Half life: 8500 years [ Alpha Decay ]
Decay Energy: 5.623MeV
Decays to
246
241
Pu.
Cm [150 neutrons]
Abundance: synthetic
Half life: 4730 years [ Alpha Decay ]
Decay Energy: 5.475MeV
Decays to
242
Pu.
Half life: 4730 years
Decay Energy: ?MeV
Decays to ?.
247
Cm [151 neutrons]
Abundance: synthetic
Half life: 1.56 x 107 years [ Alpha Decay ]
Decay Energy: 5.353MeV
Decays to
248
243
Pu.
Cm [152 neutrons]
Abundance: synthetic
Half life: 3.40 x 105 years [ Alpha Decay ]
Decay Energy: 5.162MeV
Decays to
244
Pu.
Half life: 3.40 x 105 years
Decay Energy: ?MeV
Decays to ?.
250
Cm [154 neutrons]
Abundance: synthetic
Half life: 9000 years
Decay Energy: ?MeV
Decays to ?.
Half life: 9000 years [ Alpha Decay ]
Decay Energy: 5.169MeV
Decays to
246
Pu.
Half life: 9000 years [ beta- ]
Decay Energy: 0.037MeV
Decays to
250
Bk.
Berkelium [Bk]
CAS-ID: 7440-40-6
An: 97 N: 150
Am: [247] g/mol
Group Name: Actinoid
Block: f-block Period: 7 (actinoid)
State: solid
Colour: unknown, but probably metallic and silvery white or grey in
appearance Classification: Metallic
Boiling Point: unknown
Melting Point: 1259K (986°C)
Density: (alpha) 14.78g/cm3
Density: (beta) 13.25g/cm3
Discovery Information
Who: G.T.Seaborg, S.G.Tompson, A. Ghiorso
When: 1949
Where: United States
Name Origin
After Berkeley the home town of the University of California.
"Berkelium" in different languages.
Sources
Some compounds have been made and studied. Made by bombarding americium with
alpha particles.
Uses
Berkelium has no known uses outside of basic research.
History
Berkelium was first synthesized by Glenn T. Seaborg, Albert Ghiorso, Stanley G.
Thompson, and Kenneth Street, Jr at the University of California, Berkeley in
December 1949. The team used a cyclotron to bombard a milligram-sized target of
241
Am with alpha particles to produce 243Bk (half-life 4.5 hours) and two free neutrons.
One of the longest lived isotopes of the element, 249Bk (half-life 330 days), was later
synthesized by subjecting a 244Cm target with an intense beam of neutrons.
Notes
Weighable amounts of 249Bk (half-life 314 days) make it possible to determine some of
its properties using macroscopic quantities.
Berkelium is a radioactive rare earth metal. It is named after the University of
California at Berkeley (USA). Apparently, berkelium tends to accumulate in the skeletal
system.
It is of no commercial importance and only a few of its compounds are known.
Hazards
Berkelium is radioactive. Like other actinoids, berkelium bio-accumulates in skeletal
tissue.
Isotopes of Berkelium
Notes
Berkelium has no stable isotopes.
Notable Isotopes
Bk [148 neutrons]
245
Abundance: synthetic
Half life: 4.94 days [ Electron Capture ]
Decay Energy: 0.810MeV
Decays to
245
Cm.
Half life: 4.94 days [ Alpha Decay ]
Decay Energy: 6.455MeV
Decays to
Am.
241
Bk [149 neutrons]
246
Abundance: synthetic
Half life: 1.8 days [ Alpha Decay ]
Decay Energy: 6.070MeV
Decays to
Am.
242
Half life: 1.8 days [ Electron Capture ]
Decay Energy: 1.350MeV
Decays to
246
Cm.
Bk [150 neutrons]
247
Abundance: synthetic
Half life: 1380 years [ Alpha Decay ]
Decay Energy: 5.889MeV
Decays to
Am.
243
Bk [151 neutrons]
248
Abundance: synthetic
Half life: 9+ years [ Alpha Decay ]
Decay Energy: 5.803MeV
Decays to
Am.
244
Bk [152 neutrons]
249
Abundance: synthetic
Half life: 320 days [ Alpha Decay ]
Decay Energy: 5.526MeV
Decays to
Am.
245
Half life: 320 days
Decay Energy: ?MeV
Decays to ?.
Half life: 320 days [ beta- ]
Decay Energy: 0.125MeV
Decays to
249
Cf.
Isotopes of Californium
Notes
Californium has no stable isotopes.
Notable Isotopes
248
Cf [150 neutrons]
Abundance: synthetic
Half life: 333.5 days
Decay Energy: ?MeV
Decays to ?.
Half life: 333.5 days [ Alpha Decay ]
Decay Energy: 6.361MeV
Decays to
249
244
Cm.
Cf [151 neutrons]
Abundance: synthetic
Half life: 351 years
Decay Energy: ?MeV
Decays to ?.
Half life: 351 years [ Alpha Decay ]
Decay Energy: 6.295MeV
Decays to
250
245
Cm.
Cf [152 neutrons]
Abundance: synthetic
Half life: 13.08 years [ Alpha Decay ]
Decay Energy: 6.128MeV
Decays to
246
Cm.
Half life: 13.08 years
Decay Energy: ?MeV
Decays to ?.
251
Cf [153 neutrons]
Abundance: synthetic
Half life: 898 years [ Alpha Decay ]
Decay Energy: 6.176MeV
Decays to
252
247
Cm.
Cf [154 neutrons]
Abundance: synthetic
Half life: 2.645 years [ Alpha Decay ]
Decay Energy: 6.217MeV
Decays to
248
Cm.
Half life: 2.645 years
Decay Energy: ?MeV
Decays to ?.
253
Cf [155 neutrons]
Abundance: synthetic
Half life: 17.81 days [ beta- ]
Decay Energy: 0.285MeV
Decays to
253
Es.
Half life: 17.81 days [ Alpha Decay ]
Decay Energy: 6.124MeV
Decays to
254
249
Cm.
Cf [156 neutrons]
Abundance: synthetic
Half life: 60.5 days
Decay Energy: ?MeV
Decays to ?.
Half life: 60.5 days [ Alpha Decay ]
Decay Energy: 5.926MeV
Decays to
250
Cm.
Isotopes of Einsteinium
Notes
Einsteinium has no stable isotopes.
Notable Isotopes
252
Es [153 neutrons]
Abundance: synthetic
Half life: 471.7 days [ Alpha Decay ]
Decay Energy: 6.760MeV
Decays to
248
Bk.
Half life: 471.7 days [ Electron Capture ]
Decay Energy: 1.260MeV
Decays to
252
Cf.
Half life: 471.7 days [ beta- ]
Decay Energy: 0.480MeV
Decays to
253
Fm.
252
Es [154 neutrons]
Abundance: synthetic
Half life: 20.47
Decay Energy: ?MeV
Decays to ?.
Half life: 20.47 [ Alpha Decay ]
Decay Energy: 6.739MeV
Decays to
254
249
Bk.
Es [155 neutrons]
Abundance: synthetic
Half life: 275.7 days [ Electron Capture ]
Decay Energy: 0.654MeV
Decays to
254
Cf.
Half life: 275.7 days [ beta- ]
Decay Energy: 1.090MeV
Decays to
Fm.
254
Half life: 275.7 days [ Alpha Decay ]
Decay Energy: 6.628MeV
Decays to
255
250
Bk.
Es [156 neutrons]
Abundance: synthetic
Half life: 39.8 days [ beta- ]
Decay Energy: 0.288MeV
Decays to
Fm.
255
Half life: 39.8 days [ Alpha Decay ]
Decay Energy: 6.436MeV
Decays to
251
Bk.
Half life: 39.8 days
Decay Energy: ?MeV
Decays to ?.
Isotopes of Fermium
Notes
Fermium has no stable isotopes.
Notable Isotopes
Fm [152 neutrons]
252
Abundance: synthetic
Half life: 25.39 hours
Decay Energy: ?MeV
Decays to ?.
Half life: 25.39 hours [ Alpha Decay ]
Decay Energy: 7.153MeV
Decays to
248
Cf.
253
Fm [153 neutrons]
Abundance: synthetic
Half life: 3 days [ Electron Capture ]
Decay Energy: 0.333MeV
Decays to
253
Es.
Half life: 3 days [ Alpha Decay ]
Decay Energy: 7.197MeV
Decays to
249
Cf.
Fm [155 neutrons]
255
Abundance: synthetic
Half life: 20.07 hours
Decay Energy: ?MeV
Decays to ?.
Half life: 20.07 hours [ Alpha Decay ]
Decay Energy: 7.241MeV
Decays to
251
Cf.
Fm [157 neutrons]
257
Abundance: synthetic
Half life: 100.5 days [ Alpha Decay ]
Decay Energy: 6.864MeV
Decays to
253
Cf.
Half life: 100.5 days
Decay Energy: ?MeV
Decays to ?.
Isotopes of Mendelevium
Notes
Mendelevium has no stable isotopes.
Notable Isotopes
257
Md [156 neutrons]
Abundance: Synthetic
Half life: 5.52 hours [ Electron Capture ]
Decay Energy: 0.406MeV
Decays to
Fm.
257
Half life: 5.52 hours [ Alpha Decay ]
Decay Energy: 7.558MeV
Decays to
253
Es.
Half life: 5.52 hours
Decay Energy: ?MeV
Decays to ?.
258
Md [157 neutrons]
Abundance: Synthetic
Half life: 51.5 days [ Electron Capture ]
Decay Energy: 1.230MeV
Decays to
259
Fm.
258
Md [158 neutrons]
Abundance: Synthetic
Half life: 31.8 days
Decay Energy: ?MeV
Decays to ?.
Half life: 31.8 days [ Alpha Decay ]
Decay Energy: 7.000MeV
Decays to
256
Es.
Half life: 31.8 days [ Electron Capture ]
Decay Energy: ?MeV
Decays to
Fm.
260
Half life: 31.8 days [ beta- ]
Decay Energy: 1.000MeV
Decays to
260
No.
Isotopes of Nobelium
Notes
Nobelium has no stable isotopes.
Notable Isotopes
253
No [151 neutrons]
Abundance: synthetic
Half life: 1.7 minutes [ Alpha Decay ]
Decay Energy: 8.440MeV
Decays to
Fm.
249
Half life: 1.7 minutes [ Electron Capture ]
Decay Energy: 3.200MeV
Decays to
255
253
Md.
No [153 neutrons]
Abundance: synthetic
Half life: 3.1 minutes [ Alpha Decay ]
Decay Energy: 8.445MeV
Decays to
Fm.
251
Half life: 3.1 minutes [ Electron Capture ]
Decay Energy: 2.012MeV
Decays to
259
255
Md.
No [157 neutrons]
Abundance: synthetic
Half life: 58 minutes [ Alpha Decay ]
Decay Energy: 7.910MeV
Decays to
Fm.
255
Half life: 58 minutes [ Electron Capture ]
Decay Energy: 0.500MeV
Decays to
259
Md.
Half life: 58 minutes
Decay Energy: ?MeV
Decays to ?.
Isotopes of Lawrencium
Notes
Its most stable isotope is
Lr, with a half-life of approximately 4 hours.
262