amide
Pluralamides
- 1A derivative of an oxoacid in which the hydroxyl group is replaced by an amino or substituted amino group, especially the carboxamides formed from carboxylic acids.
Much like the rivets joining steel plates, amide bonds hold the long chains of proteins and nylon together.
Each peptide bond in a protein is an amide formed between two amino acids.
Acetamide is the simplest amide derived from acetic acid.
Note
The everyday amide of organic chemistry, named from ammonia + -ide. In its commonest form, the carboxamide, a carbonyl carbon bonds straight to nitrogen. That gives the –C(=O)–N– link that holds proteins and many polymers together. Chemists say "acid amide" or "carboxamide" when they need to rule out the ionic metal compound, which shares the name but not the structure.
- 2An ionic derivative of ammonia in which a hydrogen atom has been replaced by a metal cation, yielding anions such as R-NH⁻ or R₂N⁻.
Picture removing one hydrogen from ammonia and slotting a metal in its place, the way you might replace a single brick in a wall.
Sodium amide is prepared by dissolving sodium metal in liquid ammonia.
Potassium amide acts as an extremely strong base in many reactions.
Note
Inorganic chemistry uses the same word for salts rather than covalent molecules. The nitrogen carries a negative charge, balanced by a metal cation. Sodium amide and potassium amide are the familiar reagents, prized as very strong bases. The metal is named first, as in sodium amide. That is the quickest way to tell this sense from the organic amide, whose name is built from its parent acid, as in acetamide.
Practice
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Origin
Formed from "ammonia" combined with the suffix "-ide".