A heavy silvery liquid metallic element belonging to the zinc group; a.n. 80; r.a.m. 200.59; r.d. 13.55; m.p. –38.87°C; b.p. 356.58°C. The main ore is the sulphide cinnabar (HgS), which can be decomposed to the elements. Mercury is used in thermometers, barometers, and other scientific apparatus, and in dental amalgams. The element is less reactive than zinc and cadmium and will not displace hydrogen from acids. It is also unusual in forming mercury(I) compounds containing the Hg22+ ion, as well as mercury(II) compounds containing Hg2+ ions. It also forms a number of complexes and organomercury compounds. The fact that mercury is a liquid at room temperature is a relativistic effect, as its melting point would be much higher in the absence of relativistic quantum mechanics.
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