Ate complex
An ate complex in chemistry is a salt formed by reaction of a Lewis acid with a base whereby the central atom increases its valence. (Note that in this definition the meaning of valence is equivalent to coordination number). Often in chemical nomenclature the phrase ate is suffixed to the element in question. For example, the ate complex of a boron compound is called a borate. Thus trimethylborane and methyllithium react to form the ate compound Me4B−Li+, lithium tetramethylborate(1-). This concept was introduced by Georg Wittig in 1958 The term is usually reserved for the complexes of metals in groups 2, 11 and 12.
Ate complexes are inversely analogous to onium compounds. Lewis acids form -ate ions when the central atom gains one more bond and becomes a negative anion. Lewis bases form onium ions when the central atom gains one more bond and becomes a positive cation.
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