Sulphides

Sulphides (formerly called sulphurets) are compounds consisting of sulphur united with some other element or radical, and may hence be regarded as derived fiom the compound SH₂ (sulphuretted hydrogen) by the replacement of the H by other elements. The compounds of sulphur with non~metallic elements - e.g. with chlorine, bromine, etc. - although very interesting chemically, are not of great commercial or technical importance. The metallic sulphides, however, are of great importance; many of them exist as natural deposits, and form very important ores of the metals. Examples of these are - galena, sulphide of of lead; blende, sulphide of zinc; copper pyrites, sulphides of copper and lead; cinnabar, sulphide of mercury; realgar, sulphide of arsenic, and many others. The metalic sulphides are usually hard solids insoluble in water, the sulphides of the alkalies and alkaline earths being, however, soluble. Besides their use as ores, many sulphides find other applications. Thus, pyrites are largely used as a source of sulphur or in the preparation of sulphuric acid; cinnabar is extensively used as a pigment. Most of the sulphides may be prepared artificially as white or coloured precipitates by passing sulphuretted hydrogen into acid or alkaline solutions of metallic salts. Organic sulphides are also well known, the whole class of compounds known as mercaptans being completely analogous to the metallic sulphides, while carbon disulphide (CS₂) is a most important and technically useful liquid.