Trichlor-hydroxy-platinous Acid, H₂PtCl₃(OH)

The hydrate of Trichlor-hydroxy-platinous Acid, H₂PtCl₃(OH), namely, H₂PtCl₃(OH).H₂O, is obtained as a reddish brown deliquescent mass on evaporating an aqueous solution of tetraehlor-platinous acid in vacuo over sulphuric acid and potash.

It dissolves in water, yielding a reddish brown solution with an acid reaction. Heated to 100° C. it loses water and hydrogen chloride, yielding a residue of platinum dichloride.