Sesquicarbonyl Platinum Dichloride, 2PtCl₂.3CO

Sesquicarbonyl Platinum Dichloride, 2PtCl₂.3CO, results on heating the dicarbonyl to 250° C. in a current of carbon monoxide. It may also be obtained by extracting the mixed carbonyl derivatives, resulting from passing carbon monoxide over platinous chloride, with hot carbon tetrachloride, in which it is more readily soluble, and evaporating the resulting solution. It crystallises in yellow needles, which melt at 130° C. At 250° C. it loses carbon monoxide, yielding the mono-carbonyl derivative.