An antimony phosphide and arsenide are known, as is also a thiophosphate, SbPS 4, which is prepared by heating together antimony trichloride and phosphorus pentasulphide.
The gas dissolves in water on shaking; PSF3+4H20= H 2 S+H 3 PO 4 +3HF, but is more readily taken up by alkaline solutions with the formation of fluoride and thiophosphate: PSF3+ 6NaOH = Na3PS03+3NaF.
It is slowly decomposed by water giving phosphoric and hydrochloric acids, with sulphuretted hydrogen; alkalis form a thiophosphate, e.g.
Water converts the former into ammonium thiophosphate, PO(SNH4)3.H20, whilst the latter heated to 300° in a vacuum gives thiophosphoric nitrile, NP:S (Stock, ibid., 1906, 39, p. 1967).
