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[1] [2] [3] Introduced by Gilbert N. Lewis in his 1916 article The Atom and the Molecule, a Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds. [4] Lewis structures extend the concept of the electron dot diagram by adding lines between atoms to represent shared pairs in a chemical bond.
It is named after Warren K. Lewis (1882–1975), [6] [7] who was the first head of the Chemical Engineering Department at MIT. Some workers in the field of combustion assume (incorrectly) that the Lewis number was named for Bernard Lewis (1899–1993), who for many years was a major figure in the field of combustion research. [citation needed]
In chemistry, an electron pair or Lewis pair consists of two electrons that occupy the same molecular orbital but have opposite spins. Gilbert N. Lewis introduced the concepts of both the electron pair and the covalent bond in a landmark paper he published in 1916. [1] [2]
Lewis worked with hydrogen and managed to purify a sample of heavy water. He then came up with his theory of acids and bases, and did work in photochemistry during the last years of his life. Though he was nominated 41 times, G. N. Lewis never won the Nobel Prize in Chemistry, resulting in a major Nobel Prize controversy.
In chemistry a donor number (DN) is a quantitative measure of Lewis basicity.A donor number is defined as the negative enthalpy value for the 1:1 adduct formation between a Lewis base and the standard Lewis acid SbCl 5 (antimony pentachloride), in dilute solution in the noncoordinating solvent 1,2-dichloroethane with a zero DN.
Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...
SnF 2 acts as a Lewis acid. For example, it forms a 1:1 complex (CH 3) 3 NSnF 2 and 2:1 complex [(CH 3) 3 N] 2 SnF 2 with trimethylamine, [24] and a 1:1 complex with dimethylsulfoxide, (CH 3) 2 SO·SnF 2. [25] In solutions containing the fluoride ion, F −, it forms the fluoride complexes SnF 3 −, Sn 2 F 5 −, and SnF 2 (OH 2). [26]
Tin(II) bromide can act as a Lewis acid forming adducts with donor molecules e.g. trimethylamine where it forms NMe 3 ·SnBr 2 and 2NMe 3 ·SnBr 2 [11] It can also act as both donor and acceptor in, for example, the complex F 3 B·SnBr 2 ·NMe 3 where it is a donor to boron trifluoride and an acceptor to trimethylamine.