Thermal Decomposition of Some Iron(III) Chromates

The thermal decomposition of the chromates FeOHCrO4, KFe3(CrO4)2(OH)6, Fe2(CrO4)3.H2O and Fe2(CrO4)3.3H2O have been studied by thermal analysis and Mossbauer spectroscopy. The possible presence of Fe2O(CrO4)2 as a second phase formed during the decomposition is discussed. Final products in all reactions were oxides of iron(III) and chromium(III). In addition K2Cr2O7 Was present in the reaction products for KFe3(CrO4)2(OH)6.