Lewis base

American

noun

Chemistry.

any substance capable of forming a covalent bond with an acid by transferring a pair of electrons to it.

Lewis base British

noun

a substance capable of donating a pair of electrons to an acid to form a covalent bond Compare Lewis acid

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of Lewis base

First recorded in 1960–65; named after G. N. Lewis

Example Sentences

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Lewis base

Ammonia acts as a Brønsted base because it readily accepts protons and as a Lewis base in that it has an electron pair to donate.

From Textbooks ● Feb. 14, 2019

Explain how ammonia can function both as a Brønsted base and as a Lewis base.

From Textbooks ● Feb. 14, 2019

Many Lewis acid-base reactions are displacement reactions in which one Lewis base displaces another Lewis base from an acid-base adduct, or in which one Lewis acid displaces another Lewis acid:

From Textbooks ● Feb. 14, 2019

Like ammonia, hydrazine is both a Brønsted base and a Lewis base, although it is weaker than ammonia.

From Textbooks ● Feb. 14, 2019

Being short of the preferred octet, BF3 is a very good Lewis acid and reacts with many Lewis bases; a fluoride ion is the Lewis base in this reaction, donating one of its lone pairs:

From Textbooks ● Feb. 14, 2019

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023