Phase Composition of the Products of Decomposition of Calcium Dichromate Trihydrate.

The phase transformation of calcium dichromate trihydrate during heating from 20 to 600 degree C were studied by differential-thermal, x-ray structural and IR spectroscopic analyses. It is shown that the process of dehydration is accompanied by hydrolysis of the dichromate leading to the formation of CaCrO//4 and CrO//3. The temperature limits of the existence of the CrO//2 phase are determined. Schemes for the thermal decomposition of calcium dichromate trihydrate under conditions of polythermal heating and in the presence of hydrolysis occurring in parallel with the transformations are proposed.