Topotactic oxidation of NaCrS2

The topotactic deintercalation of NaCrS2 by iodine in refluxing acetonitrile and in a solid–vapour reaction at different temperatures is studied. The resulting products are metastable CrS2−x (x∼0.1) or stable Cr2S3 according to the reaction temperature. Starting at ∼550°C, Cr2S3 is topotactically transformed to Cr2O3 in an oxygen-bearing argon atmosphere.