Dicarbonyl Platinum Dichloride, PtCl₂.2CO

Dicarbonyl Platinum Dichloride, PtCl₂.2CO, is obtained by heating the monocarbonyl to 150° C. in a current of carbon monoxide. Upon sublimation in the gas it yields colourless needles melting at 142° C. to a yellow liquid. If raised to the melting-point in air, carbon monoxide is evolved. The residue solidifies and melts again at 190° C. A little above this temperature further decomposition sets in.

Dry hydrogen is without action in the cold, but at the melting-point the compound is at once reduced to the metal. If the hydrogen is burned the flame becomes luminous and, if made to impinge upon a cold porcelain surface, deposits a black film of platinum. Dry chlorine has no action until 80° or 90° C., when the compound fuses.

The dicarbonyl is decomposed by water, the chief reaction being as follows 2:

PtCl₂.2CO + H₂O = CO₂ + CO + Pt + 2HCl.