The simplest aliphatic compounds, such as diazo-methane, diazoethane, and azo-formic acid, are yellow; the diamide of the latter acid is orange-red.
Willstatter (Ber., 1900, 33, p. 1164) obtained this acid by the action of a methyl alcoholic solution of ammonia on dibrompropylmalonic ester at 140° C., the diamide formed being then hydrolysed either by hydrochloric acid or baryta water: CH 2 CBr(C02H) 2 CH 2.
Ammonia also reacts immediately, giving phosphorus diamide, P(OH)(NH2)2, and the corresponding ammonium salt.
The diamide, PN 2 H 4, was obtained by Hugot (ibid., 1905, 141, p. 1235) by acting with ammonia gas on phosphorus tribromide or tri-iodide at -70 0; it is very unstable, and decomposes at -25°.
The diamide, PO (NH 2) (NH), results when the pentachloride is saturated with ammonia gas and the first formed chlorophosphamide, PC1 3 (NH 2) 2, is decomposed by water.