Carbonyl Platinum Monoxide, PtO.CO

Carbonyl Platinum Monoxide, PtO.CO, is presumably obtained when the hydrochloric acid solution of the carbonyl platinum dichloride is stirred into an acidified solution of ammonium acetate. The liquid becomes violet in colour, and then deposits a bluish black, flocculent precipitate of what is presumably the carbonyl monoxide.

It is soluble in concentrated hydrochloric acid, yielding a yellow solution of the carbonyl platinum dichloride. With alkalies it reacts as follows:

PtO.CO + 2NaOH = Pt + Na₂CO₃ + H₂O.

Stable in vacuo and in air, even on gently warming, it decomposes with slight explosion at 300° to 400° C., yielding metallic platinum and carbon dioxide.