Corrosive sublimate HgCl

Mercury(II) chloride, HgC, corrosive sublimate, m.p. 280 C, b.p. 302"C. Essentially covalent material (Hg plus CL Hg plus aqua regia). Forms complex halide ions, e.g. (HgCU) (HgCL)" in excess HCl and forms complexes. Very poisonous. 

Again, mercury is apparently a monad in mercurous ohlo ride (calomel, HgCl) and a dyad in mercuric chloride (corrosive sublimate, Hg"Cl,)j but there are strong reasons for believing that the formula of calomel ought to bo doubled, in which case mercury would assume the dyad form in both com pounds ... 

Mercuric Chloride, Mercury bichloride corrosive sublimate mercury perchloride corrosive mercury chloride. CljHg mol wt 271.52. Cl 26.12%, Hg 73.88%. HgCl,. 

Syn. Calomel—Occurs sparingly as horn quicksilver in the mineral kingdom. May be prepared either by subliming a mixture of bichloride of mercury and mercury, HgCl, -j- Hg, which yields 2 HgCl or by adding hydrochloric acid or solution of common salt to a solution of protonitrate of mercury, when the protochloride is precipitated. HgO, NOj - - NaCl = NaO, NO, - - HgCl. It is a heavy white volatile powder, insoluble in water. It is blackened by alkalies. When first prepared, it is always contaminated with corrosive sublimate, and must be well washed with hot water before it is used as a medicine. 

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