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http://chemistry.iitd.ac.in/faculty/elias.html
Instructor
: Prof. Anil J. Elias
Room: MS 733: IIG1

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http://web.iitd.ac.in/~elias/ProblemsinPblock.html
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(check iitd website for dates)
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Inorganic chemistry: Huheey, keiter and keiter
Inorganic Chemistry: Housecroft and Sykes

IIT Delhi 2014

Instructor: Prof. Anil J. Elias, Room: MS 733: IIG1

3000 BC
Dancing Girl a bronze statuette dating around
2500 BC, from the Mohenjodaro site
Zebu Bull from Mohenjo-Daro and Harappa
Pure tin candlestick
Bronze, an alloy of tin and copper was the first alloy to be used around 3000 BC.
After 600 BC pure metallic tin was produced.

Tyrian purple, a reddish purple organobromine natural dye was used by ancient
Phoenicians. The dye was produced from the secretions of a species of sea snails in the family, Muricidae. The chemical component (main ingredient: 6, 6’- dibromoindigo) was discovered in 1909 by Paul Friedlaender.

The three philosophical principles of alchemy: salt, sulfur and mercury
“ Bring sulfur, old nurse, that cleanses all pollution, and bring me fire that I may purify the house with sulfur”
Homers’ Odyssey
Fumigating power of sulfur mentioned by Homer. Sulfur is also mentioned in the Bible as brimstone.

Sulfuric acid and alcohol first prepared by the physician, alchemist and writer from Bagdad, Abu Bekr
Zakariya Razi (Rhazes)
In 1746 in Birmingham, England, John Roebuck began producing sulfuric acid in lead-lined chambers, which were stronger, less expensive, and could be made much larger than the glass containers which had been used previously.

Albertus Magnus, a catholic saint (Albert the Great, 1193 –1280) is believed to have been the first to isolate arsenic by heating soap together with arsenic trisulfide ( orpiment As
2
S
3 along with realgar, As
4
S
4
).

1669
The Alchemist Discovering Phosphorus : a painting by Joseph Wright
Hennig Brandt discovers phosphorus from reductive distillation of urine concentrate by evaporating urine to dryness and distilling the residue with sand.

1694
Boyle rejects the
Aristotelian theory of the four elements (earth, air, fire, and water) and also the three principles (salt, sulfur, and mercury) proposed by Paracelsus.
3
4
4
10
4
10

1772
J. J. Becher proposed the phlogiston theory
phlogiston theory is an obsolete scientific theory that postulated a fire-like element called phlogiston, contained within combustible bodies, that is released during combustion.
Daniel Rutherford isolates N
2 gas after he removed oxygen and carbon dioxide from
the air mixture. He named the isolated gas as noxious air or phlogisticated air and believed it was exhaled by the mouse which he used in the experiment to remove oxygen by breathing.

1772
Scheele isolates oxygen gas by heating manganese dioxide (and later potassium nitrate and mercuric oxide) but did not publish his findings immediately.
It was also independently discovered by Joseph Priestly by heating and decomposing
mercuric oxide in 1774.

dephlogisticated muriatic acid air
Carl Wilhelm Scheele
1774, 1777
Schwefelluft ”
Carl Wilhelm Scheele discovers chlorine gas from HCl in 1774. He discovered hydrogen sulphide gas when he treated ferrous sulfide or pyrite (fool’s gold) with a mineral acid, which released a gas with the smell of rotten eggs. He referred to this gas as stinkede (stinking) and called it “Schwefelluft” meaning sulfur air.

Gay Lussac
Red phosphorus
Thenard
Gay Lussac and Thenard discovers PCl
3 and also PCl current of chlorine over heated red phosphorus .
5 by passing a slow

Nitrogen compounds as explosives
Dulong
Pierre Louis Dulong prepares nitrogen trichloride, NCl
3 fingers and an eye in two explosions. An NCl
3 and looses two explosion also blinded
Humphry Davy (famous for Davies Safety lamp) triggering him to hire
Michael Faraday as a co-worker.

Silicon: a versatile element with myriad aplications
Silicon discovered by Berzelius from the reduction of potassium fluorosilicate with metallic potassium:

Contact process for sulphuric acid patented by the British vinegar merchant
Peregrine Phillips. In addition to being a more economical process for concentrated sulfuric acid than the previous lead chamber process, the contact process also produces sulfur trioxide and oleum. Sulfuric acid is the second largest inorganic chemical produced worldwide (200 million tonnes)

Friedrich W ö hler
Father of Synthetic
Organic Chemistry
Cl
Cl
Cl Cl
P
N N
P
N
P
Cl
Cl
OR
N P
OR n
210-250
0
C
RONa
-NaCl
Cl
N P
Cl n
NHR
N P
NHR n or
RNH
2
R
2
NH
-HCl
NR
2
N P
NR
2 n
RM
(Organometallic agent)
R
N P
Cl n
W ö hler statue at G ö ttingen
J. Liebig and F. W ö hler prepares the inorganic heterocycle cyclophosphazene , N
3
P
3
Cl
6 from the reaction of PCl
5 and NH
4
Cl.
3 Si + 2 N
2
→ Si
3
N
4 (1857)

Mn 2+
C.F. Schoenbein detects and names ozone from its characteristic odour after a lightning storm

lead–acid battery
The French physicist Gaston Planté discovers the lead–acid battery, the oldest type of rechargeable battery

1886
Henri Moissan prepared fluorine gas, F
2 by the electrolysis of a solution of potassium hydrogen difluoride in liquid hydrogen fluoride. For this discovery he received the
Nobel prize in 1906.

1890-1894
3
3
Curtius
1890
The common synthesis method is the "Wislicenus process," which proceeds in two steps from ammonia. In the first step, ammonia is converted to sodium amide:
2 Na + 2 NH
3
→ 2 NaNH
2
+ H
2
The sodium amide is subsequently combined with nitrous oxide:
2 NaNH
2
+ N
2
O
→ NaN
3
+ NaOH + NH
3
Alternatively the salt can be obtained by the reaction of sodium nitrate with sodium amide.
Wislicenus
(1892)

1904
F. S. Kipping
F.
S.
Kipping coins the word "silicone" to describe polydiphenylsiloxane by analogy of its formula, with the formula of benzophenone

In 1937 after 30 years of research, Kipping In the Bakrerian lecture of the
Royal Society said “ The prospect of any immediate and important advance in this section of organic chemistry does not seem to be very hopeful."
Me
2
Si Cl
4 lit
2
Me
Me
Si O
Me
O
Si
Me
O Si
Si
O
Me
Me
Me
Me
H
2
O
12 lit
Me
Me
Si O
Me
O
Si
Me
O Si
Si
O
Me
Me
Me
Me
42%
+ Trimer (0.5%)
Pentamer (7%)
Hexamer (2%)
Me
3
Si O Si Me
3
Thermal and/or by acid or base catalyst
(eg. conc. H
2
SO
4
)
Me
3
Si O
Me
Si O Si Me
3
Me n
Poly dimethyl siloxane PDMS
Lowest glass transition temperature, Tg = -127 °C

Sir William Ramsay
In 1901-1902 Ramsay had been asked to advise the Indian government on the founding of a science institute and the institute was established in Bangalore with the help of the Government of Mysore and JN Tata. Ramsay suggested his student
Morris Travers as a possible director for this institute and in 1906, Travers was appointed as the director of the new Indian Institute of
Science
Morris M. Travers
(1862-1961)
Sir William Ramsay discovered neon, krypton, and xenon and received
Nobel Prize in 1904. He also isolated helium which had been observed in the spectrum of the sun but had not been found on earth till then.
In
1910 he also made and characterized radon. (1894 argon with Lord Raleigh)

1907
The first light emitting diode (LED) made of SiC
Gallium arsenide (GaAs)
Henry Joseph Round
Aluminium gallium arsenide (AlGaAs)
Silicon carbide
Gallium phosphide
Indium gallium nitride etc
To the Editors of Electrical World:
SIRS: – During an investigation of the unsymmetrical passage of current through a contact of carborundum and other substances a curious phenomenon was noted. On applying a potential of 10 volts between two points on a crystal of carborundum, the crystal gave out a yellowish light. Only one or two specimens could be found which gave a bright glow on such a low voltage, but with 110 volts a large number could be found to glow. In some crystals only edges gave the light and others gave instead of a yellow light green, orange or blue. In all cases tested the glow appears to come from the negative pole, a bright blue-green spark appearing at the positive pole. In a single crystal, if contact is made near the center with the negative pole, and the positive pole is put in contact at any other place, only one section of the crystal will glow and that same section wherever the positive pole is placed.
There seems to be some connection between the above effect and the e.m.f. produced by a junction of carborundum and another conductor when heated by a direct or alternating current; but the connection may be only secondary as an obvious explanation of the e.m.f. effect is the thermoelectric one. The writer would be glad of references to any published account of an investigation of this or any allied phenomena.
New York, N. Y.
H. J. Round

Haber
1909
Bosch
•Fritz Haber reports Haber process for the catalytic synthesis of NH
3 which was made into a large scale industrial process along with C. Bosch in 1913.
• Haber received the Nobel Prize in Chemistry in 1918.
•According to an estimate, nearly 80% of nitrogen present in the human tissue has had its origins from Haber process.
•The worldwide production of ammonia exceeds 140 million tonnes and is the third largest inorganic chemical produced in the world.

Alfred Stock- the father of boron hydride chemistry
B. P
B
2
B
4
B
5
B
5
B
6
H
H
H
H
H
10
B
10
6
10
9
11
H
-92.5 °C
16 °C
58 °C
65 °C
108 °C
14
213°C
m.p. 99.7 °C
Alfred Stock prepares a series of boron hydrides including B
2
H
6 and separates them using the first sophisticated vacuum manifold. Due to their very high air and moisture sensitivity and flammability, till then they were not separable. He published his work in 1933.
Mg
3
B
2
+ H
3
PO
4
(aq) B
4
H
10
, B
5
H
9
, B
6
H
10
B
2
H
6
+ 2NaH
2
PO
4
+ H
2
NaBH
4
+ H
3
PO
4
B
2
H
6 pyrolysis
B
4
H
10
, B
5
H
9
, B
5
H
11
, B
10
H
14

Borazine: The Inorganic Benzene
First reported in 1926 by Alfred Stock and Pohland
H
N
H
B
N
H H
N
H
B
N
H
H
B B
H
3 B
2
H
6
+ 6 NH
3
→ 2 B
3
N
3
H
6
+ 12 H
2
N
H
An alternative more efficient route begins with lithium borohydride and ammonium chloride:
3 LiBH
4
+ 3 NH
4
Cl → B
3
N
3
H
6
+ 3 LiCl + 9 H
2
H
B
Borazine is isostructural with benzene. The six B-N bonds have length of 1.436 Å. The carbon-carbon bond in benzene is shorter length at 1.42 Å. The boron-nitrogen bond length is between that of the B -N (1.51
Å ) and the B=N (1.31 Å). This suggests partial delocalization of nitrogen lone pair.
N
H
B
H
Probability Distributions for borazine (left) and benzene (right)
Borazine has the same colligative properties as benzene, however the two are very different chemically. The electron density along the boron-nitrogen bond is not distributed evenly, due to the difference in electro negativities between the two atoms. Therefore, the molecular orbitals of the system are lumpy in appearance.
This uneven distribution makes borazine makes it prone to addition reactions.

1935 H J Taylor
Aerial view of Chernobyl reactor

1938
Roy J. Plunkett
Poly tetrafluoroethylene (Teflon) accidentally discovered by Roy J. Plunkett of kinetic chemicals (A subsidiary of DuPont) while attempting to make a new CFC using tetrafluoroethylene. He observed that there was no gas flowing out of a small cylinder of tetrafluoroethylene whose weight indicated no loss of substance.
On cutting open the cylinder, he observed a waxy white highly slippery solid on its interior walls whose analysis indicated polymerized tetrafluoroethylene.

Thomas Midgley: A daring inventor
To show that his chlorofluorocarbon (CFC) coolant, Freon, is nontoxic and nonflammable, Thomas Midgley Jr. takes the stage at an ACS national meeting, inhales a lungful of
Freon, and blows out a candle
.
J.R. McNeill an environmental historian remarked that Midgley had more impact on the Earth’s atmosphere than any other living organism due to his inventions : namely, lead gasoline additives and chlorofluorocarbons.
However, Midgley wasn’t killed by these inventions which we now know to be exceptionally harmful. He met his maker thanks to a bed that he created after contracting polio and becoming bedridden at the age of 51. The bed featured a complex system of ropes and pulleys to help Midgley’s attendants get him out of bed…ropes which eventually strangled him.
In 1941, the American Chemical Society gave Midgley its highest award, the Priestley
Medal This was followed by the Willard Gibbs Award in 1942. He also held two honorary degrees and was elected to the United States National Academy of Sciences. In 1944, he was elected president and chairman of the American Chemical Society

E.G. Rochow
Industrial success of Silicones

ITO resistive capacitive
G. Rupprecht reports the semi conducting properties of Indium oxide, In
2
O
3
.
This was followed by the report by V. A. Williams in 1966 on the potential of tin doped indium oxide (Indium tin oxide, ITO) as a transparent conducting material. ITO is a solid solution of indium(III) oxide and tin(IV) oxide , typically
90% In
2
O
3
, 10% SnO
2 by weight. It is the most widely used transparent conducting oxide, especially as films because of its electrical conductivity , optical transparency , as well as the ease of depositing as thin films.
Applications include liquid crystal, flat panel and plasma displays, touch screen technology of mobile phones and
ATM’s, electronic ink, light-emitting diodes, solar cells, antistatic coatings, defrosting aircraft wind shields and infrared reflecting coatings.

The discovery of the first noble gas reaction
In March of 1962, Bartlett set up a glass apparatus containing PtF
6
, a red gas in one container and xenon, a colorless gas in an adjoining container, separated by a seal. Here's his recollection of the ensuing experiment, which he conducted while working alone in his laboratory: "Because my co-workers at that time
(March 23, 1962) were still not sufficiently experienced to help me with the glassblowing and the preparation and purification of PtF
6
[platinum hexafluoride] necessary for the experiment, I was not ready to carry it out until about 7 p.m. on that Friday. When I broke the seal between the red PtF
6 gas and the colorless xenon gas , there was an immediate interaction, causing an orangeyellow solid to precipitate . At once I tried to find someone with whom to share the exciting finding, but it appeared that everyone had left for dinner!"
The reaction took place at room temperature "in the twinkling of an eye" and was "extraordinarily exhilarating," recalls Bartlett. He was certain that the orange-yellow solid was the world's first noble gas compound. But convincing others would prove somewhat difficult. The prevailing attitude was that no scientist could violate one of the basic tenets of chemistry: the inertness of noble gases. That orange-yellow solid was subsequently identified in laboratory studies as xenon hexafluoroplatinate (XePtF
6
), the world's first noble gas compound.

Metalla
Carboranes
M. F Hawthorne
1965
B
10
H
14
+ 2 Et
2
S
(n-Pr)
2
O
-H
2
B
10
H
12
(Et
2
S)
2
HC CH
H
2
, Et
2
S
C
2
B
10
H
12
C
2
B
10
H
12
+ MeO + 2MeOH
[C
2
B
9
H
12
]
2
+ NaH
85 °C
[C
2
B
9
H
12
]
2
+ H
2
+ B(OMe)
3
[C
2
B
9
H
11
]
2
+ H
2
+ Na nido 7,8 [C
2
B
9
H
11
]
2
+ FeCl
2
 5
[7,8 (C
2
B
9
H
11
)]
2
Fe
2
“olla” metallacarborane
Fe

Allen K. Breed
One azido group contributes about 335 kj/mol ( 80 kcal/mol) of endothermicity to a compound
Allen K. Breed uses sodium azide, NaN
3 along with a collision sensor in automobile airbags (instead of compressed air) and achieves inflation of the airbag under 30 milliseconds required for collision safety

Wade’s Rules
Ken Wade,
Durham
B
2
H
6
+ 2 Et
3
N
2 Et
3
N. BH
3
B
4
H
10
, 190 °C
[Et
3
NH]
2
[B
12
H
12
]
For borane and carborane clusters, the structures are based on deltahedra , which are polyhedra in which every face is triangular . The clusters are classified as closo-, nido-, arachno- or hypho-, based on whether they represent a complete (closo-) deltahedron, or a deltahedron that is missing one (nido-), two
(arachno-) or three (hypho) vertices .
Boron hydride Name No. of skeletal electron pairs
Examples
[B n
H n
] 2or B n
H n+2
B n
H n+4
Closo
Nido n+1 n+2
B
6
H
6
2, B
12
H
12
2-
B
2
H
6
,B
5
H
9
, B
10
H
14
B n
H n+6
Arachno n+3
B n
H n+8
Hypho n+4
Each BH unit furnishes 2 skeletal bonding electrons
Each additional H· furnishes 1 skeletal bonding electron
Ionic charges must be included in the electron count
B
4
H
10
B
5
H
12


Earl R. Stadtman (b. 1919) and
Theresa C. Stadtman (b. 1920)
Selenocysteine is the 21st proteinogenic amino acid. It exists naturally in all kingdoms of life as a building block of selenoproteins. Selenocysteine is a cysteine analogue with a selenium-containing selenol group in place of the sulfur-containing thiol group. It is present in severalenzymes (for example glutathione peroxidases, tetraiodothyronine 5' deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases etc). Selenocysteine was discovered by biochemist Theresa
Stadtman, wife of Earl R. Stadtman, at the National Institutes of Health.

ROBERT WEST
“Why do you want to climb mount Everest”?
“Because it‘s there”
George Mallory :British mountaineer, 1886-1924
2.160
Å

1991
Anthony J.
Arduengo, III
Carbene Is Genie In A Bottle
Chemists are particularly drawn to molecules that behave like ferocious cats , reacting rapidly and often violently and hence cannot seem to resist the temptation to control them.
One such species is the carbene which is imperative for an entire framework of organic reactions thereby leading to an altogether a separate branch named--Carbene Chemistry .

5
+
Karl O. Christe
First N
5
+ (pentazenium) compound, N discovered by Karl O. Christe. N
5
+
5
+ AsF
6
cation is a highly energetic ion with a calculated endothermicity of 1471.8 kJ/mol.
One azido group contributes about 335 kj/mol (80 kcal/mol) of endothermicity to a compound

Konrad Seppelt
first metal-xenon compound where xenon acts as a ligand
Konrad Seppelt discovers the first metal-xenon compound where xenon acts as a ligand achieved by reduction of AuF
3 with xenon. The AuXe
4
2+ (Sb
2
F
11
)
2 complex had a square planar gold with a Au-Xe bond distance of 274 pm.

Jemmis’ rules
E.D. Jemmis,
I.I.Sc, Bangalore
Jemmis draws together a number of corollaries to Wade's rules into a single, easily employed general rule ,"
Thomas P. Fehlner
Jemmis ’ mno rule states that m + n + o skeletal electron pairs are necessary for a closed macropolyhedral system to be stable
HC
BH
CH
BH
Fe
H
B
BH
BH
BH
BH
BH
B
H
[(7,8-C
2
B
9
H
11
)Fe(Cp)]
1 m+n+o+p = 2+17+1+1= 21 skeletal e count
9 BH= 9 pairs
7 CH = 10.5 pairs
Fe
2+
= 1 pair
1- = 0.5 pair total = 21 pairs stable
[or (m + n + o + p) for systems having open polyhedra as well].
Here m = number of condensed polyhedra n = number of vertices o = number of single atom bridges between two polyhedra p = number of vertices missing for open polyhedra if present.
For example, for nido clusters p = 1 and for arachno clusters p = 2. For a benzene ring or cyclopentadienyl ring as such p = 2 and if it is already in an

6 or

5 mode, p= 1.
For transition metals, the oxidation state of the metal should be known and the number of electrons for the electron count should be taken as the same as the number of electrons lost by the neutral metal atom to reach that oxidation state; for example, Fe3+ gives 3 electrons.
The uniqueness of Jemmis’ mno rules is that they are not only applicable to macropolyhedral clusters but also applied to polyhedra, metallocenes, and even unsaturated cyclic organic compounds. Interestingly, Jemmis’ rules get reduced to Wade’s rules when m = 1 and o = 0 (one polyhedron).

Akiro Sekiguchi
first silicon-silicon triple bond
Akiro Sekiguchi prepares the first silicon-silicon triple bonded compound

Sir Andre Geim
• Stronger than steel: 200 times
• Thinner than hair: 1 million times
• Worlds most conductive material
• Stretchable, transparent, flexible permeable
• Worlds first 2D material
Graphene
Geim was awarded the 2010 Nobel Prize in Physics jointly with Novoselov "for groundbreaking experiments regarding the two-dimensional material graphene".
Graphene consists of one-atom-thick layers of carbon atoms arranged in two-dimensional hexagons, and is the thinnest material in the world, as well as one of the strongest and hardest.The material has many potential applications and is considered a superior alternative to silicon. Geim's achievements include the discovery of a simple method for isolating single atomic layers of graphite, known as graphene. The team published their findings in October 2004 in Science

Douglas Stephan
Douglas W. Stephan discovers the first example of a frustrated Lewis acid base pair based on boron and phosphorus. Due to their unquenched reactivity such molecules are able to heterolytically cleave dihydrogen molecule making them potential metal free hydrogenation catalysts.

GREG ROBINSON
B=B
2007
2008
Si=Si
(0 state)
2007-2008
G.M Robinson proposed the first gallium –gallium triple bonded compound in 1997 which evoked the famous comment from F.A Cotton that, " That's no more a triple bond than I'm the Dalai Lama!"
2.229
Å

K Tamao
K Tamao prepares a stable germanone molecule having a Ge=O bond. This is the first example of a heavier element ketone analogue

Holger Braunschweig
First example of a stable diboryne having a B

B and stabilized by N-heterocyclic carbenes prepared by Holger Braunschweig

Borospherene
Lai-Sheng Wang
Lai-Sheng Wang at Brown University in Providence, Rhode Island, and his colleagues have made a cage-like molecule with 40 boron atoms by vaporizing a chunk of boron with a laser then freezing it with helium, creating boron clusters.
The team analyzed the energy spectra of these clusters and compared them with computer models of 10,000 possible arrangements of boron atoms. The matching configuration revealed they had created the boron ball.
Unlike carbon buckyballs, in which the faces are made of hexagons and pentagons, the boron buckyball is made from triangles, hexagons and heptagons. As a result, it is less spherical but still an enclosed structure. Wang has dubbed the molecule
"borospherene". The team is now hunting for a boron analogue of graphene – a strong sheet of carbon just one atom thick that is often touted as a "wonder" material because of its unique electrical properties. ( july 12, 2014 Nature
Chemistry )