Abstract Organic oximides may be concisely defined as “bodies containing the chemical group HZN'OH attached to a carbon atom.” These bodies may be broadly divided into two classes: (a) Those whose preparation involves the use of hydroxylamine; these are known as “oximes,” whence the generic name “oximide” is derived. (b) Those which are prepared independently of hydroxylamine. These latter may be obtained by the aid of nitrous acid, and have been termed “isonitroso-” bodies. This group =N.OH must be distinguished from the true “nitroso-” group —NO. The oxime group is bivalent, being regarded as a compound of trivalent nitrogen with the monovalent radical hydroxyl. The true nitroso-group is monovalent, two “affinities” of the nitrogen being taken up by oxygen.