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.
The disulphide, CaS2, and pentasulphide, CaS 5, are formed when milk of lime is boiled with flowers of sulphur.
The -y-diketones are characterized by the readiness with which they yield furfurane, pyrrol and thiophene derivatives, the furfurane derivatives being formed by heating the ketones with a dehydrating agent, the thiophenes, by heating with phosphorus pentasulphide, and the pyrrols by the action of alcoholic ammonia or amines.
Two sulphides of antimony are definitely known, the trisulphide Sb 2 S 3 and the pentasulphide Sb2S5; a third, the tetrasulphide Sb2S4, has also been described, but its existence is doubtful.