“…Past solid state investigations contain studies of the hydrated nitrate of nickel and the hydrated nitrate of cobalt with hydrated alumina, «-alumina, hydrated iron oxide, chromium trioxide, and chromium(ic) oxide, separately, over temperature ranges extending from 260°to 1200°C. (3,4,6). This report is concerned with the decompositions, transformations, and reactions that occur when chromium trioxide and/or chromium (ic) oxide, mixed separately with the hydrated nitrates of copper and zinc, are calcined in air at various temperatures ranging from 260°to 1200°C.…”