Production and Chemical Properties

The conversion of an intimate mixture of Cr(III) and Cr(VI) compounds into Cr02 under hydrothermal conditions has been developed into an industrial process in autoclaves at ca. 350 °C and 300 bar [5.18]. 

Pure Cr02 slowly disproportionates in the presence of water. The Cr02 crystal surface of commercial pigments is therefore topotactically converted to [i-CrOOH, which serves as a protection layer [5.20]. In the absence of moisture, Cr02 is stable up to ca. 400 °C, above this temperature it decomposes to form Ct203 and oxygen. 

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