By the addition of sulphuretted hydrogen to the nitriles, or by the action of phosphorus pentasulphide on the acid-amides.
A pentasulphide B2S5 is prepared, in an impure condition, by heating a solution of sulphur in carbon bisulphide with boron iodide, and forms a white crystalline powder which decomposes under the influence of water into sulphur, sulphuretted hydrogen and boric acid.
A thiophenol, C 6 H 5 SH, is known, and is prepared by the action of phosphorus pentasulphide on phenol, or by distilling a mixture of sodium benzene sulphonate and potassium sulphydrate.
Phosphorus pentasulphide at 140 - I 50° C. converts it into xanthion by transformation of > CO to > CS (R.
Gabriel, Ber., 1891, 4, 7 3; 1896, 29, p. 2610); and by the action of phosphorus pentasulphide on acyl-O-bromalkylamides (A.