Ceroceric oxide

Ceroceric oxide, Ce₄O₇ or Ce₇O₁₂. - When cerium dioxide is heated to a red heat in a current of dry hydrogen free from air, it is partially reduced and loses in weight by about 2 per cent. The reduction proceeds most rapidly with an oxide that has not previously been intensely ignited, but such an oxide is liable to have retained a little water; accordingly it is difficult to obtain reliable analytical data concerning the product formed by the reduction. The lower oxide is considered to correspond to the violet ceroceric hydroxide (described below) and to the acid salt known as ceroceric hydrosulphate; hence Meyer regards it as Ce₄O₇, and Wyrouboff and Verneuil as Ce₇O₁₂. It is a blue or bluish-black solid which readily absorbs oxygen and is sometimes pyrophoric.