Mercury sulfide Mercury sulfide Mercury sulfide, mercuric sulfide, mercury sulphide, or mercury(II) sulfide is a chemical compound composed of the chemical elements mercury and sulfur. It is represented by the chemical formula HgS. It is virtually insoluble in water. HgS is dimorphic with two crystal forms: Crystals of red, α-HgS, are optically active. This is caused by the Hg-S helices in the structure. β-HgS is precipitated as a black powder when HS is bubbled through solutions of Hg(II) salts. β-HgS is unreactive to all but concentrated acids. Mercury metal is produced from the cinnabar ore by roasting in air and condensing the
Metal (or their alloys) with relatively low melting points. Such metals include zinc, cadmium, tin, antimony (here counted as a metal), lead, and bismuth, some of which are quite toxic. In Britain, the fine art trade uses the term "white metal" in auction catalogues to describe foreign silver items which do not carry British Assay Office marks, but which are nonetheless understood to be silver and are priced accordingly. A heavy metal is any relatively dense metal or metalloid. More specific definitions have been proposed, but none have obtained widespread acceptance. Some heavy metals have niche uses, or are notably toxic;