Cadmium Chromate, CdCrO4, may be obtained by heating a solution of the dichromate with cadmium hydroxide, in a sealed tube, at 200° C., when it separates as a bright orange-yellow crystalline powder. It is insoluble in water, which, when boiling, decomposes it. If the mother-liquor from the above preparation is allowed to stand for a time, it deposits crystals of the dihydrate CdCrO4.2H2O.
Basic cadmium chromates, e.g. 5CdO.2CrO3.H2O, have been described. Basic double salts, e.g. (NH4)2O.4CdO.4CrO3.3H2O and K2O.4CdO.4CrO3.3H2O, are formed when an alkali chromate is added to solutions containing excess of cadmium salt; with excess of potassium chromate the double salt, K2Cd(CrO4)2.2H2O, results; sodium chromate yields only alkali-free basic salts. Several ammoniated compounds have been described. |