Possible mechanisms for the precipitation of cations with thioacetamide are considered. I n some cases the cation is precipitated by the hydrogen sulfide liberated in the hydrolysis of thioacetamide. In other cases a metal-thioacetamide intermediate is formed.In a study a t room temperatures carbon containing intermediates were obtained in the reaction in acid solution between thioacetamide and cuprous or cupric chloride, cuprous or cupric bromide or mercuric chloride. No carbon containing intermediates were isolated for the other cations studied. The empirical formulas for the copper-thioacetamide compounds were C2HsNSCuCl and CIHsNSCuBr.The stoichiometry of the precipitation reactions was determined, and copper was found to be present in the cuprous form.The X-ray powder diffraction patterns for these two compounds were satisfactorily indexed assuming hexagonal unit cells. The conditions of formation, solubility, stability and chemical properties of these compounds were investigated. The infrared spectra of these compounds, thioacetamide, n-substituted thioamides, tetrakisthioacetamide cuprous and argentous chloride and s-ethyl thioimidoacetate hydrochloride were determined. Structures in which the thioacetamide is in the thion form and in which the copper of the cuprous halide is apparently either coordinately bound to nitrogen or t o nitrogen and sulfur are consistent with the observed properties of these two compounds.The evidence for the existence of such compounds is reviewed.
IntroductionThioacetamide is used as a reagent in precipitating cations as metallic sulfides in qualitative3 and quantitative4 analysis. The stoichiometric equation for these precipitations is