The Pnictogens
Physical Properties of Pnictogens
Molar Mass (g)
Nitrogen
14.01
Atomic Radii
(pm)
Electronegativity
Electron Affinity
(kJ/mol)
Ionization Energy
(kJ/mol)
Electron
Configuration
74
3
-3
1400
[He]2s22p3
[Ne]3s23p3
Phosphorous
30.97
110
2.1
70
1060
Arsenic
74.92
121
2
78
966
121.76
141
1.9
103
833
Antimony
[Ar]3d104s24p3
[Kr]4d105s25p3
[Xe]4f145d106s26p
H3PO3
Bismuth
208.98
170
1.9
91
774
3
Table 14.1 pg 348 Shriver & Atkins
Arsenic
* Just looking at Group 15 of the PTE we find that the group follows the
trends of the PTE except when you look at the Electron Affinity. The EA
gets larger as you proceed down the group until you reach Bismuth.
Bismuth’s EA is smaller than that of Antimony. The reason is the fact
that the f-shell of Bismuth is full. This lowers the zeffective of Bismuth, and
in turn reduces the EA.
Liquid Nitrogen
Bismuth
Antimony Ore
Oxidation States
„
Physical Properties
-
3 Oxidation State
-
Nitrogen and Phosphorous take on a 3 oxidation state because they are nonmetals of the 15th Group.
„
3+ Oxidation State
„
„
Arsenic, Antimony, and Bismuth all easily take on a 3+ oxidation state because they
are metalloids of the 15th Group.
„
5+ Oxidation State
This state is rare, but occurs with Arsenic in such molecules such as
[Tetraphenylarsenic(V)] bromide. Arsenic in this case has an oxidation state of 5+
because each Ph has a negative charge. All of these elements can achieve this oxidation
state, but it takes less energy to get to another oxidation state.
„
Inert Pair Effect
You would expect the elements in this group to have an oxidation state of either 3
or 5+ . The reason that the metalloids have the 3+ oxidation state is because of the
„
inert pair effect. This means that the oxidation state of the element is 2 less
than expected
„
Form intermetallic bonds with metals
Form covalent bonds with most nonmetals
Increasing size of ions going down the
group leads to a decrease in the
strength of covalent linkages P > As >
Sb > Bi
All act as Lewis bases with basicity
decreasing As > Sb > Bi
1
NITROGEN
„
Low reactivity
Bond strength, HOMO-LUMO gap,
low polarizability
{ Haber process
{
Nitrogen
„
Reactivity & Application
Compounds
Azides
Hydrides
{ Halides
{ Oxygen Compounds
{
{
http://www.bbc.co.uk/schools/gcsebitesize/chemistry/usefulproductsair/ammonia_haberrev3.shtml
USES OF NITROGEN
Nitrogen’s Uniqueness
•Ammonia
synthesized by
Haber process
„
{
„
•Applied directly
to soil
„
Coordination number is
usually smaller than
other Group 5 elements
Small atomic radius
{
Fertilizer!
Capable of negative
oxidation states
No d orbitals
{
•Odda process:
Conversion of
nitric acid to
calcium nitrate
High electronegativity
Harder, more likely to
make ionic-type bonds
2
Reactivity
Phosphorous
„
Reactivity and Uses
Phosphorous with Metals
„
Red phosphorous can be reacted with
metals in an inert atmosphere to form
either metal or phosphorous-rich
phosphides.
Phosphorous
reacts with itself
readily to form the
allotropes: white
phosphorous, red
phosphorous and
black phosphorous
„
Phosphorous also
reacts readily with
oxygen and
hydrogen, although
it is able to react
with almost any
element on the
periodic table.
General Uses
„
„
„
Phosphorus is used extensively in
pyrotechnics, steel making and alloy
making.
Phosphoric acid, H3PO4 is used in
fertilizers.
Phosphorus is used in electrode-less
plating:
{
Ni2+(aq)+2H2PO2-(aq)+H2O(l)=>Ni(s)+2H2PO3-(aq)+H2(g)+2H+(g)
3
Oxides
The Other Elements
„
„
„
N and P
oxides
As and Sb oxides
Bi oxides
ACIDIC
AMPHOTERIC
BASIC
Arsenic, Antimony, & Bismuth
„
„
Reactivity Trends
„
„
„
All act as Lewis bases with basicity
decreasing As > Sb > Bi
Hydrides of As, Sb, Bi are exceedingly
poisonous and thermally unstable
As, Sb, Bi react with halides to form
MX3, MX5, and halide complexes of MIII
and MV
As, Sb, Bi most readily oxidized to +3
state [As2O3, Sb2O3, and Bi2O3]
Also oxidize to +5 state [As4O10,
H3AsO4, Sb2O5, Bi2O5]
Organometallic Compounds
„
„
„
„
All three elements form a wide range
of organometallic compounds in both
the +3 and +5 state
Can form both M-C single bonds and
M=C double bonds
Stability of M-C bond strength
decreases in the order of As > Sb > Bi
Aryl more stable than alkyl compounds
4
Applications
„
References
Compounds of As, Sb and Bi with the
metals of group III (Al, Ga, In, Tl) are
important semiconductors
{
{
{
Arsenic
and
antimony
are in
LED’s!
{
Look! LED’s on
motorcycles!
Amazing!
{
Shriver & Atkins, Inorganic Chemistry
Chemistry of the Elements Greenwood &
Earnshaw
Brown, Iverson, Foote. Organic Chemistry
http://en.wikipedia.org/wiki/Odda_Process
http://en.wikipedia.org/wiki/Fertilizer
www.ironthunder.com
References (Pictures!)
http://images.google.com/imgres?imgurl=http://img.alibaba.com/photo/11750174/Liquid_Nitrogen_Generator.jp
g&imgrefurl=http://drean1952.trustpass.alibaba.com/product/11750174/Liquid_Nitrogen_Generator.html
&h=480&w=640&sz=39&hl=en&start=19&tbnid=47KHFbEKD0rZ5M:&tbnh=103&tbnw=137&prev=/imag
es%3Fq%3Dnitrogen%2Bpictures%26gbv%3D2%26svnum%3D10%26hl%3Den%26client%3Dfirefoxa%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DG
http://images.google.com/imgres?imgurl=http://img.alibaba.com/photo/50215233/Phosphorous_Acid__H3PO3_
.jpg&imgrefurl=http://tongchem.en.alibaba.com/offerdetail/50833278/Sell_Phosphorous_Acid_H3PO3_.h
tml&h=360&w=360&sz=12&hl=en&start=2&tbnid=BdBoHHYXnh6GxM:&tbnh=121
&tbnw=121&prev=/images%3Fq%3Dphosphorous%2Bpictures%26gbv%3D2%26svnum%3D10%26hl%
3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DG
http://images.google.com/imgres?imgurl=http://www.hedegaard.com/Minerals/Species/ArsenicJachymov.jpg&i
mgrefurl=http://www.hedegaard.com/Minerals/Species/Arsenic.html&h=646&w=697&sz=44&hl=en&start
=21&tbnid=djHonZtv15fRVM:&tbnh=129&tbnw=139&prev=/images%3Fq%3Darsenic%2Bpictures%26st
art%3D20%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26client%3Dfirefoxa%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DN
http://images.google.com/imgres?imgurl=http://img.alibaba.com/photo/11505448/Antimony_Ore.jpg&imgrefurl=
http://www.alibaba.com/catalog/11505448/Antimony_Ore.html&h=480&w=640&sz=56&hl=en&start=2&t
bnid=FSCFIC6d3XZg6M:&tbnh=103&tbnw=137&prev=/images%3Fq%3Dantimony%2Bpictures%26gbv
%3D2%26svnum%3D10%26hl%3Den%26client%3Dfirefoxa%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DG
http://images.google.com/imgres?imgurl=http://webmineral.com/specimens/Bismuth1.jpg&imgrefurl=http://web
mineral.com/specimens/picshow.php%3Fid%3D1068&h=863&w=606&sz=94&hl=en&start=1&tbnid=pL4
xdOwFELRqeM:&tbnh=145&tbnw=102&prev=/images%3Fq%3Dbismuth%2Bpictures%26gbv%3D2%26
svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:enUS:official%26sa%3DG
5