It may be obtained in small quantity by passing ethylene or acetylene into boiling sulphur; by passing ethyl sulphide through a red-hot tube; by heating crotonic acid, butyric acid or erythrite with phosphorus pentasulphide; by heating succinic anhydride with phosphorus pentasulphide or sodium succinate with phosphorus trisulphide (J.
The thiophen homologues are best prepared by heating the 1.4 diketones with phosphorus pentasulphide, the diketones reacting in the enolic form: Thiotenol, or oxymethyl thiophene, is prepared by heating laevulinic acid with phosphorus pentasulphide (W.
There are three known compounds of arsenic and sulphur, namely, realgar As2S2, orpiment As2S3, and arsenic pentasulphide As2S5.
Arsenic pentasulphide,As2S5, can be prepared by fusing the trisulphide with the requisite amount of sulphur; it is a yellow easily-fusible solid, which in absence of air can be sublimed unchanged; it is soluble in solutions of the caustic alkalis, forming thioarsenates, which can also be obtained by the action of alkali polysulphides on orpiment.
The corresponding sulphur compound, thiophosphoryl fluoride, PSF 3, obtained by heating lead fluoride and phosphorus pentasulphide to 200°, is a colourless gas, which may be condensed to a clear transparent liquid.