醯胺(amide)

两类含氮有机化合物的统称，与氨、胺有关，并包含一个羟基（－C＝O；参阅functional group）。第一类，共价醯胺是由氨基（－NR2，其中R可以代表一个氢原子，或代表一个有机的联合基团，如甲基）取代酸中的羟基（－OH）而生成。由羧酸制得的醯胺称羧醯胺，除了最简单的甲醯胺为液体外，均为固体。它们不导电，具高沸点，液态的共价醯胺是优良的溶剂。简单的有机共价醯胺没有实际的天然来源，然而生命系统中的和蛋白质都是些带键（参阅covalent bond）的长链（聚合物），这些都是醯胺链结。尿素是一种带两个氨基的醯胺。具有重要商业价值的共价醯胺中有若干种用作溶剂；其他的有磺胺药以及尼龙。第二类，离子（类似盐类）醯胺是将共价醯胺、胺或氨用能起反应的金属（如钠）处理後得到的，具有很强的硷性。

English version：

amide

Any member of either of two classes of nitrogen-containing organic compounds related to ammonia and amines and containing a carbonyl group (&singlehorzbond;C&doublehorzbond;O; see functional group). The first class, covalent amides are formed by replacing the hydroxyl group (&singlehorzbond;OH) of an acid with an amino group (&singlehorzbond;NR2, in which R may represent a hydrogen atom or an organic combining group, such as methyl). Amides formed from carboxylic acids, called carboxamides, are solids except for the simplest, formamide, a liquid. They do not conduct electricity, have high boiling points, and (when liquid) are good solvents. There are no practical natural sources of simple covalent amides, but the peptides and proteins in living systems are long chains (polymers) with peptide bonds (see covalent bond), which are amide linkages. Urea is an amide with two amino groups. Commercially important covalent amides include several used as solvents; others are the sulfa drugs and nylon. The second class, ionic (salt-like) amides (see ionic bond), are made by treating a covalent amide, an amine, or ammonia with a reactive metal (e.g., sodium) and are strongly alkaline.