Sidgwick, Nevil Vincent

Selenium, bis(diethyldithiocarbamato)-stereochemistry, 60 Selenium, bis(dithiofurancarbamato)-stereochemistry, 60 Selenium(II) complexes bis(dithiochelate), 60 Selenocyanate complexes linkage isomers, 186 Selenonium ions, trifluoro-stereochemistry, 37 Self-exchange reactions, 333 electron transfer rate constants, 347-353, 366 rate constants calculation, 348 rate constants, 362 Semicarbazide, 1,4-diphenylthio-ruthenium determination, 546 Semi-glycinecresol red metallochromic indicator, 557 Semi-xylenol orange metallochromic indicator, 557 Seven-coordinate compounds stereochemistry, 69-83 Sidgwick, Nevil Vincent, 16 Silicon, tris(acetylacetone)-configuration, 195... 

Sidgwick, Nevil Vincent (1873-1952) British chemist. The first notable contribution by Sidgwick to chemistry was his book The Organic Chemistry of Nitrogen (1910). He subsequently became interested in the electronic structure of atoms, including work on coordination compounds and the hydrogen bond. He summarized his research in an influential book The Electronic Theory of Valency (1927). He spent the rest of his career trying to understand compounds in terms of valence theory. This culminated in his monumental two-volume book The Chemical Elements and their Compounds (1950). 

The first attempts to interpret Werner s views on an electronic basis were made in 1923 by Nevil Vincent Sidgwick (1873—1952) and Thomas Martin Lowry (1874—1936).103 Sidgwick s initial concern was to explain Werner s coordination number in terms of the sizes of the sub-groups of electrons in the Bohr atom.104 He soon developed the attempt to systematize coordination numbers into his concept of the effective atomic number (EAN).105 He considered ligands to be Lewis bases which donated electrons (usually one pair per ligand) to the metal ion, which thus behaves as a Lewis acid. Ions tend to add electrons by this process until the EAN (the sum of the electrons on the metal ion plus the electrons donated by the ligand) of the next noble gas is achieved. Today the EAN rule is of little theoretical importance. Although a number of elements obey it, there are many important stable exceptions. Nevertheless, it is extremely useful as a predictive rule in one area of coordination chemistry, that of metal carbonyls and nitrosyls. 

M. Laing, Nevil Vincent Sidgwick, 1873-1952 one of the unsung truly greats , J. Chem. Educ., 1994, 71, 47-473. 

Tizard, H. T. (1954). Nevil Vincent Sidgwick, 1873—1952. Obituary Notices of Fellows of the Royal Society 9(1) 236-258. 

In 1923, Nevil Vincent Sidgwick (1873-1952) and Thomas Martin Dowry (1874-1936) made the first attempts to interpret Werner s views on an electronic basis. Sidgwick tried to... 

Nevil Vincent Sidgwick and H. M. Powell Nonbonding pairs of electrons and stereochemistry... 

In 1934 Nevil Vincent Sidgwick published a paper in which he established the well-known Effective Atomic Number rule for the bonding and stoichiometry of transition metal carbonyl compounds (2), For the metals of even atomic number Z, he observed that if each carbonyl group bonded to the metal atom is considered to "donate two electrons to the metal atom (in its oxidation state of zero), then the sum of the atomic number, Z, of the metal plus two times the number of CO groups attached to it equals the atomic number of the next heavier inert gas. This worked beautifully for the 3d metals, i.e., Cr in Cr(CO)5, Fe in Fe(CO)5, and Ni in Ni(CO)4. All had an Effective Atomic Number of 36, Z of krypton. This idea was quicldy extended to deal with transition metals with odd atomic numbers and to groups that donated one or three electrons, e,g, Mn in Mn2(CO)iQ (to give a Mn—Mn covalent bond) and Co in Co(CO)3(NO) and Fe in Fe(CO)2(NO)2 in which the NO molecule contributed 3 electrons. 

We inorganic coordination chemists will be forever grateful for this combination of the visionary ideas of Nevil Vincent Sidgwick and the painstaking development of these ideas by Ron Gillespie that has given to us this remarkable pair of valuable tools — EAN and VSEPR. 

Together with Ralph Howard Fowler, Nevil Vincent Sidgwick (1873-1952) played a leading role in the emergence and consolidation of quantum chemistry both in the United Kingdom and the United States. 

Sutton, L. E. 1975. Nevil Vincent Sidgwick. Dictionary of Scientific Biography, Vol. 12, 418-420. New York Scribner s. 

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