Mercury sulfide properties

Zylberajeh, C., Ruaudel-Teixier, A., and Barraud, A., Properties of inserted mercury sulfide layers in a Langmuir-Blodgett matrix. Thin Solid Films, 179, 9, 1989. 

The toxic effects of mercury and mercury compounds as well as their medicinal properties have been known for many centuries. In the first century AD, Pliny indicated the use of mercuric sulfide (cinnabar or vermilion) in medicine and in cosmetics. This compound was probably known to the Greeks in the time of Aristotle (13). 

Some metal thiosulfates are inherently unstable because of the reducing properties of the thiosulfate ion. Ions such as Fe " and Cu " tend to be reduced to lower oxidation states, whereas mercury or silver, which form sulfides of low solubiUty, tend to decompose to the sulfides. The stabiUty of other metal thiosulfates improves in the presence of excess thiosulfate by virtue of complex thiosulfate formation. 

The most important mercury chalcogenide halides are of the type HgaYjXj (Y = S, Se, Te X = Cl, Br, I). The corresponding sulfide halides have been known for over 150 years (326). Quite a lot of work has been performed concerning the preparation, structures, electronic and optical properties, and phototropic behavior of these compounds. Mercury chalcogenide halides of other compositions have been mentioned in the literature (141). As most of these compounds are not well established, they will not be treated in detail, with the exception of the latest contributions (see Table V). 

The properties of anodic layers of HgS formed on mercury in sulfide solutions have been investigated in comparison with anodic sulfide layers of cadmium and bismuth. Also, the electrochemistry of mercury electrodes in aqueous selenite solutions has been studied (see Sect. 3.2.1). The problem with the presence of several cathodic stripping peaks for HgSe in acidic Se(IV) solutions has been addressed using various voltammetric techniques at a hanging-mercury-drop electrode [119]. 

Elemental composition Hg 86.22%, S 13.78%. The compound may be identified from its physical properties and also by x-ray methods. The compound may be heated in a current of air and SO2 formed may be analyzed by GC-FID or GC-FPD. Mercury(II) sulfide may be digested with aqua regia, diluted appropriately, and analyzed for mercury metal by AA using cold vapor method or by ICP-AES (see Mercury). 

The melting points of these isomers are very sensitive to impurities (see properties). The diethyl sulfide used in these preparations is freed of mercaptan impurities by shaking with mercury(II) oxide, followed by filtration and distillation only the fraction boiling at 92 to 93° is used. 

The mercuric compounds, in which mercury is bipositive, differ somewhat in their properties from the corresponding compounds of zinc and cadmium. The differences are due in part to the very strong tendency of the mercuric ion, Hg + +, to form covalent bonds. Thus the covalent nvstal mercuric sulfide, HgS, is far less soluble than cadmium sulfide or zinc sulfide (Chap. 22). 

Property Mercury Mercuric (II) chloride Mercuric (II) sulfide Mercurous (I) chloride... 

Sulfur has been known since prehistoric times. Because it is flammable, alchemists regarded sulfur as essential to combustion. The chemical properties of sulfur and its compounds, including the reaction of sulfur with mercury (Hg) to form a red solid, mercuric sulfide (HgS), and the use of sulfuric acid (H2SO4) as a solvent of metals, were discovered at about C.E. 250-300. Gunpowder, a mixture of sulfur, charcoal, and potassium nitrate (KNO3), was first used for military purposes in China in C.E. 904. 

The physico-chemical properties of the stable Tl(I)-compounds are in some points similar to those of the salts of the Group I elements (high water-solubility of sulfate and carbonate) as well as to those of silver, mercury, and lead compounds (poor water-solubility of chloride, bromide, iodide, sulfide). 

One of the most tantalizing chemical transformations known to ancient practitioners of inorganic chemistry involved roasting of mercuric sulfide ores such as cinnabar to form hydrargyrum or quicksilver (60). As the toxic properties of mercury became more widely appreciated in the middle ages, formulations of the metal and its salts were used in medical applications. 

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