Invoked by the possibility that chromium chromate species might constitute the surface composition of calcined chromia catalysts, a commercial Cr-2(CrO4)(3). 6H(2)O compound was examined by thermogravimetry and differential scanning calorimetry in different reactive gas atmospheres. The principle goal was a proper assessment of its thermal and chemical stabilities with the hope of making an objective judgment on current environmental reservations about industrial applications of calcined chromia catalysts, owing to volatility of Cr-IV-O species. On the basis of the thermal analysis results, the chromate compound was calcined at some selected temperatures in the range from 150 degrees C to 1000 degrees C. The solid products were, then, subjected to X-ray powder diffractometry and spectroscopies of infrared absorption and UV-Vis diffuse reflectance. The results have shown the parent bulk chromate to dehydrate completely near 300 degrees C and to decompose into chromate-covered alpha-Cr2O3 particles at 450-1000 degrees C, encompassing formation of noncrystalline polychromate (Cr1+xO4+3x2-) and nonstoichiometric gamma-Cr2O3+x, bulk phases. in the presence of hydrogen atmosphere, the dehydration is intercepted by an immediate reduction, however the eventual product (alpha-chromia) remained chromate covered to 1000 degrees C. The high-temperature thermal and chemical stabilities thus revealed for the dispersed chromates an attributed to electronic interactions with nearby Cr-III-O species dwelled in a crystalline lattice.