Red Mercuric Sulfide

Submitted by Lyman C. Newell, R. N. Maxson, and M. H. FilsonI Checked by W. C. FerneliusJ 

When hydrogen sulfide reacts, with mercuric chloride in neutral or acid solution, or when mercury and sulfur are ground together, black mercuric sulfide is formed. Under certain conditions, this material can be converted into the red modification by the continued action of soluble alkali sulfides. The reaction of mercuric chloride and sodium thiosulfate gives the red form if the ratio of the concentrations is higher than 1 4d The red sulfide is also produced when the substance Hg(SH)NCS is boiled with concentrated ammonium thiocyanate solution or when hydrogen sulfide is conducted into a warm mercuric salt solution in the presence of acetic acid and an excess of ammonium thiocyanate, or thiourea.2,3 

Thirty-five grams of mercuric acetate and 25 g. of ammonium thiocyanate are dissolved in 100 ml. of hot glacial acetic acid. A steady stream of hydrogen sulfide is conducted into the hot solution until precipitation is complete. Then the acetic acid is slowly evaporated. (Caution Hydrogen cyanide gas is evolved.) The black precipitate that first appears slowly changes to the red modification as the acid boils away. Until this change is 

When the acid is completely removed, cool, add 200 ml. of distilled water, and filter on a Buchner funnel. Wash and dry the product between sheets of absorbent paper. Yield 25 g. (98 per cent). 

If mercuric chloride is used instead of the acetate, a larger amount of acetic acid is required, and a longer period of heating is needed. The color changes from black, through brown, tan, and orange to red, but the final color is never so brilliant a vermilion as that of the material prepared from the acetate. 

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Mercuric Sulfide. Mercuric s A ide[1344 8-5] HgS, exists ia two stable forms. The black cubic tetrahedral form is obtaiaed when soluble mercuric salts and sulfides are mixed the red hexagonal form is found ia nature as cinnabar (vermilion pigment). Both forms are very insoluble in water (see Pigments, inorganic). Red mercuric sulfide is made by heating the black sulfide in a concentrated solution of alkah polysulfide. The exact shade of the pigment varies with concentration, temperature, and time of reaction. 

The element does not occur in nature in native form. Its principal mineral is cinnabar, the red mercuric sulfide, HgS. Black mercuric sulfide, metacinnabar, also is found in nature. Other ores are hvingstonite, HgSh4S coloradite, HgTe tiemannite, HgSe and calomel, HgCl. Its concentration in the earth s crust is estimated to be 0.08 mg/kg. The average concentration in sea water is about 0.03 ag/L. 

Cinnabar. A native red mercuric sulfide, HgS. It was used in some pyrotechnic compns. See Davis (1943), 61 and under Sulfides... 

Details for carrying out lecture demonstrations of (a) dyeing a mixed fabric blue and yellow simultaneously from the same bath, and (b) separating, by flotation, red mercuric sulfide, followed by green cupric silicate from their mixture with sand, will be found in the first four editions of this book. The degree of selectivity shown, in chromatography, by cellulose, alumina, and silica also lends itself to demonstrations. 

Malonic Mononitrile Cyanoacetic Acid Mercuric Sulfide, Red Mercuric Sulfide... 

In the 70, Peter [128] studied the mechanism for the formation of CdS in an alkaline medium. The anodization was performed on polished polycrystalline cadmium rods in a solution of 0.1 M Na2S and IM NaHCO. A reference electrode consisted of a pool of mercury in contact with red mercuric sulfide (-0.74 V vs SHE). A voltammogram is showed on the Figure 11. 

A third form of cadmium pigments includes the mercury cadmiums. Mercuric sulfide (HgS) forms soHd solutions up to about 20 mol % with the oranges, reds, and maroons. The heat stabiUty is improved up to 370°C, and the costs are somewhat lower than the CP grades. The mercury cadmiums are slightly more reactive, but have excellent bleed resistance. 

Mercuric sulfide (HgS) is dimorphic. The more common form, cinnabar (red a-form), has a distorted RS, trigonal structure which is unique among the monosulfides, for the crystal is built of helical chains in which Hg has two nearest neighbors at 2.36 A, two more at 3.10 A, and two at 3.30 A. Bulk a-HgS is a large-gap semiconductor (2.1 eV), transparent in the red and near IR bands. The rare, black mineral metacinnabarite is the 3-HgS polymorph with a ZB structure, in which Hg forms tetrahedral bonds. Upon heating, 3-HgS is converted to the stable a-form. The ZB structure of HgS is stabilized under a few percent admixture of transition metals, which replace Hg ions in the lattice. 

Mercury (chemical symbol Hg, from the Latin name of the metal, hydrar-gyrium, liquid silver), previously also known as quicksilver is, at ordinary temperatures, a silvery white liquid metal that boils at 360°C. The metal is occasionally found in nature in the native state. Most mercury has been derived, however, from the red mineral cinnabar (composed of mercuric sulfide) that was also used in the past as a red pigment known as vermilion (see Textbox 41). The Greek philosopher Aristotle, writing in the fourth... 

Venetian red inorg chem A pigment with a true red hue contains 15-40% ferric oxide and 60-80% calcium sulfate. va nesh an red verdigris See cupric acetate. vard-a.gres ( vermiiion See mercuric sulfide. var mil-yan (... 

Mercuric Sulfide, Black (Ethiops Mineral) Mercuric Sulfide, Red (Vermillion,Artificial Cinnabar, Chinese Red)... 

Magnesium chloride, anhydrous, 29 Manganous chloride, anhydrous, 29 Mercuric sulfide, red, 19 Mercury, solubility of metals in, 6 Metals, solubility in mercury, 6 Monochloroamine, 59 analysis of, 62... 

A red form of mercuric sulfide which is formed by grinding mercury and sulfur together in the presence of potassium sulfide. 

The addition of H2S or alkali metal sulfides to aqueous Hg2+ precipitates the highly insoluble, black mercuric sulfide, HgS. This black solid when heated or treated in other ways is changed into a red form that is identical to the mineral cinnabar. In this red form, HgS has a distorted NaCl structure in which (Hg—S) , chains can be recognized. Red cinnabar on irradiation in aqueous KI is converted to black cinnabar, which has the ZnS structure and also occurs in Nature. 

Mercuric sulfide, HgS, is formed as a black precipitate when hydrogen sulfide is passed through a solution of a mercuric salt It can also be made by rubbing mercury and sulfur together in a mortar The black sulfide (w hich also occurs in nature as the mineral metacinna-barite) is converted by heat into the red form (cinnabar). Mercuric sulfide is the most insoluble of metallic sulfides. It is not dissolved even by boiling concentrated nitric acid, but it does dissolve in aqua regia, under the combined action of the nitric acid, which oxidizes the... 

The abundance of mercury in Earth s cmst is estimated to be about 0.5 parts per million. That makes it one of the 20 least common elements. It very rarely occurs as an element. Instead, it is usually found as a compound. Its most common ore is cinnabar, or mercuric sulfide (HgS). Cinnabar usually occurs as a dark red powder. It is often called by the common name of vermillion or Chinese vermillion. 

Paints often contain solvents such as toluene, xylene, halogenated aromatic hydrocarbons, and methylene chloride, as well as heavy metals in their pigments including chromium yellow, lemon yellow (barium chromate), vermilion red (cadmium and mercuric sulfides), and flake white (lead). Both acute and chronic exposures to toluene and xylene are associated with neurotoxicity and can also damage the liver and kidneys. 

Mineral poisons were also well known in the ancient world. In particular, the ores and compounds of arsenic, antimony, copper, mercury, and lead were familiar to many cultures. Pseudo-Dioscorides detailed the poisonous effects of arsenic (meaning sometimes the sulfide, sometimes the white oxide), litharge (red lead or lead oxide), cinnabar (mercuric sulfide), and white lead (lead acetate). Hippocrates, Nicander, Dioscorides, Galen, and Paul of Aegina wrote clinical accounts of lead poisoning, of which there were occasional epidemics, and miners were known to be at risk from the fumes created by smelting processes. 

Inorganic mercury compounds occur when mercury combines with elements such as chlorine, sulfur, or oxygen. These mercury compounds are also called mercury salts. Most inorganic mercury compounds are white powders or crystals, except for mercuric sulfide (also known as cinnabar) which is red and turns black after exposure to light. 

Color Silver-white (liquid metal) tin-white White (solid mercury) Black or grayish-black (mercuric sulfide, black) bright scarlet-red blackens on exposure to light (mercuric sulfide, red) White... 

Physical state Heavy, mobile, liquid metal Solid mercury is ductile, maleable mass which may be cut with a knife Crystals, granules or powder rhombic crystals, crystalline solid0 Heavy amorphous powder, also occurs as black cubic crystals (mercuric sulfide, black) powder, lumps, hexagonal crystals (mercuric sulfide, red) Heavy powder rhombic crystals or crystalline powder 1... 

Mercuric sulfide, or cinnabar, was reported to be used in tattooing dyes to produce a red pigmentation (Bagley et al. 1987 Biro and Klein 1967). An analysis of finger paints and make-up paints manufactured... 

Mercuric sulfide, or cinnabar, was reported to be used in tattooing dyes to produce a red pigmentation (Bagley et al. 1987 Biro and Klein 1967). An analysis of finger paints and make-up paints manufactured in Europe showed that they all contained less than 1 ppm mercury (Rastogi 1992). The author did not discuss whether these products are available in the United States. While some of medicinal and pharmaceutical uses of mercury compounds have been replaced in recent years, individuals in some ethnic or religious groups may still use mercury in various traditional remedies, ceremonies, and rituals. 

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