Reihlen and Flohr demonstrated that Wolffram’s salt could be prepared directly by mixing aqueous solutions of the colorless [[Pt(etn)4Cl2|[Pt(etn)]Cl]] and its yellow analogue, [Pt(etn)Cl]Cl, where etn = NHCHCH, leading to the most probable conclusion of the double salt formula, [Pt(CHNH)Cl] [Pt(CHNH)]Cl·4HO, compared with concurrently postulated explanations of tervalent platinum.