CYL 503: Chemistry of the main group elements and solids

1. CYL 503: Chemistry of the main group elements and solids • Shapes of molecules, symmetry and group theory • Hypervalency and d orbital participation • Space groups • Boron group • Carbon group • Nitrogen group • Oxygen group • Halogen group • Rare gases http://chemistry.iitd.ac.in/faculty/elias.html Instructor: Prof. Anil J. Elias Room: MS 733: IIG1

2. Evaluation and material • One quiz on revision of fundamentals (5marks) 10 questions from http://web.iitd.ac.in/~elias/ProblemsinPblock.html • Minor 1 (25 Marks) (check iitd website for dates) • MInor2 ( 25 Marks) • Major ( 45 Marks) Material: What the instructor teaches! Lecture Notes/powerpoint slides will be provided from time to time Books: Inorganic chemistry: Huheey, keiter and keiter Inorganic Chemistry: Housecroft and Sykes Your duty: Attend Classes and be punctual (8.00.00 AM)

5. IIT Delhi 2014

7. Landmark discoveries in the chemistry of p block Elements An introductory lecture presentation to main group chemistry Instructor: Prof. Anil J. Elias, Room: MS 733: IIG1

8. 3000 BC Dancing Girl a bronze statuette dating around 2500 BC, from the Mohenjo-daro 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.

9. ~1570 BC 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.

10. ~800 BC 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.

11. 940 AD Sulfuric acid and alcohol first prepared by the physician, alchemist and writer from Bagdad, Abu BekrZakariyaRazi (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. 

12. 1250 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 As2S3 along withrealgar, As4S4).

13. 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.

14. 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. Robert Boyle makes P4O10 by oxidation of yellow phosphorus and H3PO4 by hydrolysis of P4O10.

15. 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 N2 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.

16. 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.

17. 1774, 1777 dephlogisticated muriatic acid air Schwefelluft” Carl Wilhelm Scheele Carl Wilhelm Scheele discovers chlorine gas from HCl in 1774. He discoveredhydrogen 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.

18. 1808 Gay Lussac Thenard Red phosphorus Gay Lussac and Thenard discovers PCl3 and also PCl5 by passing a slow current of chlorine over heated red phosphorus.

19. 1811 Nitrogen compounds as explosives Dulong Pierre Louis Dulong prepares nitrogen trichloride, NCl3 and looses two fingers and an eye in two explosions. An NCl3 explosion also blinded Humphry Davy (famous for Davies Safety lamp) triggering him to hire Michael Faraday as a co-worker.

20. 1824 Silicon: a versatile element with myriad aplications Silicon discovered by Berzelius from the reduction of potassium fluorosilicate with metallic potassium:

21. 1831 Contact process for sulphuric acid 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)

22. 1834 Friedrich Wöhler Father of Synthetic Organic Chemistry Wöhler statue at Göttingen J. Liebig and F. Wöhler prepares the inorganic heterocyclecyclophosphazene, N3P3Cl6 from the reaction of PCl5 and NH4Cl. 3 Si + 2 N2 → Si3N4 (1857)

23. 1840 Mn2+ C.F. Schoenbein detects and names ozone from its characteristic odour after a lightning storm

24. 1859 lead–acid battery The French physicist Gaston Planté discovers the lead–acid battery, the oldest type of rechargeable battery

25. 1886 Henri Moissan prepared fluorine gas, F2 by the electrolysis of a solution of potassium hydrogen difluoride in liquid hydrogen fluoride. For this discovery he received the Nobel prize in 1906.

26. 1890-1894 The Azides: MN3 and RN3 Wislicenus (1892) 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 NH3 → 2 NaNH2 + H2 The sodium amide is subsequently combined with nitrous oxide: 2 NaNH2 + N2O → NaN3 + NaOH + NH3 Alternatively the salt can be obtained by the reaction of sodium nitrate with sodium amide.

27. 1904 F. S. Kipping F. S. Kipping coins the word "silicone" to describe polydiphenylsiloxane by analogy of its formula, with the formula of  benzophenone

28. Silicone Polymers 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." Lowest glass transition temperature, Tg = -127 °C

29. 1904 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 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)

30. 1907 The first light emitting diode (LED) made of SiC Gallium arsenide (GaAs)Aluminium gallium arsenide (AlGaAs) Silicon carbide Gallium phosphide Indium gallium nitride etc Henry Joseph Round To the Editors of Electrical World: SIRS: – During an investigation of the unsymmetrical passage of current through a contact of carborundumand 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

31. 1909 Haber Bosch • Fritz Haber reports Haber process for the catalytic synthesis of NH3 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.

32. Alfred Stock- the father of boron hydride chemistry 1912 • Alfred Stock prepares a series of boron hydrides including B2H6 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.

33. Borazine: The Inorganic Benzene First reported in 1926 by Alfred Stock and Pohland 3 B2H6 + 6 NH3 → 2 B3N3H6 + 12 H2 An alternative more efficient route begins with lithium borohydride and ammonium chloride: 3 LiBH4 + 3 NH4Cl → B3N3H6+ 3 LiCl + 9 H2 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 (1.51Å ) and the B=N (1.31 Å). This suggests partial delocalization of nitrogen lone pair. 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.

34. 1935 H J Taylor Aerial view of Chernobyl reactor

35. 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.

36. Thomas Midgley: A daring inventor 1941 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 Midgleyhad 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

37. Industrial success of Silicones E.G. Rochow

38. 1954 ITO resistive capacitive G. Rupprecht reports the semi conducting properties of Indium oxide, In2O3. 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% In2O3, 10% SnO2 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.

39. 1962 The discovery of the first noble gas reaction In March of 1962, Bartlett set up a glass apparatus containing PtF6, 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 PtF6 [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 PtF6 gas and the colorless xenon gas, there was an immediate interaction, causing an orange-yellow 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 (XePtF6), the world's first noble gas compound.

40. MetallaCarboranes M. F Hawthorne 1965 “olla” metallacarborane

41. 1967 One azido group contributes about 335 kj/mol ( 80 kcal/mol) of endothermicity to a compound Allen K. Breed Allen K. Breed uses sodium azide, NaN3 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

42. 1971 Wade’s Rules Ken Wade, Durham 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. 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

43. 1976 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, thioredoxinreductases, formatedehydrogenases, glycinereductases etc). Selenocysteine was discovered by biochemist Theresa Stadtman, wife of Earl R. Stadtman, at the National Institutes of Health.

44. 1981 “Why do you want to climb mount Everest”? “Because it‘s there” George Mallory :British mountaineer, 1886-1924 Robert West 2.160Å Robert West makes the first stable silicon–silicon double bonded compound

45. 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. Anthony J Arduengo III prepares the first stable carbenenow well known as the NHC or N-Heterocyclic Carbene

46. 1999 Pentazenium, N5+ Karl O. Christe First N5+ (pentazenium) compound, N5+ AsF6- discovered by Karl O. Christe. N5+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

47. 2000 first metal-xenon compound where xenon acts as a ligand KonradSeppelt KonradSeppelt discovers the first metal-xenon compound where xenon acts as a ligand achieved by reduction of AuF3 with xenon. The AuXe42+(Sb2F11-)2 complex had a square planar gold with a Au-Xe bond distance of 274 pm.

48. Jemmis’ rules 2001 Jemmis draws together a number of corollaries to Wade's rules into a single, easily employed general rule," Thomas P. Fehlner E.D. Jemmis, I.I.Sc, Bangalore Jemmis’ mno rule states thatm + n + o skeletal electron pairs are necessary for a closed macropolyhedral system to be 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).

49. 2004 first silicon-silicon triple bond AkiroSekiguchi AkiroSekiguchiprepares the first silicon-silicon triple bonded compound

50. 2004 • Stronger than steel: 200 times • Thinner than hair: 1 million times • Worlds most conductive material • Stretchable, transparent, flexible permeable • Worlds first 2D material Graphene Sir Andre Geim 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