Imidotrithiophosphoric Acid, HN=P(SH)₃

Imidotrithiophosphoric Acid, HN=P(SH)₃, was a yellow liquid having a density of 1.78, and like its ammonium salt, was insoluble in all the solvents which were tried. It was dissociated only at a high temperature, but was partly hydrolysed by water, thus

HN=P(SH)₃ + 3H₂O = OP(OH)₂(SNH₄) + 2H₂S

With liquid hydrogen chloride this acid formed the addition product HN=P(SH)₃.HCl.

The action of ammonia on phosphorus halides gives either ammoniates or, by elimination of all hydrogen as ammonium chloride, halonitrides. The amides, which should be formed as intermediate products, seem to be difficult to isolate from the true halides, although the oxyhalides and thiohalides readily yield such compounds. Exceptionally, phosphorus diamidotrifluoride, PF₃(NH₂)₂, was prepared as a white mass by the following reaction:—

PF₃Cl₂ + 4NH₃ = PF₃(NH₂)₂ + 2NH₄Cl