Cinnabar HgS

Mercury (Quicksilver, Hydrargyrum), Hg, at wt 200.61, silvery liq, mp —38.87°, bp 356.9°, d 13.546g/cc at 20°. Insol in w, HC1, ale and eth sol In nitric acid. Sometimes found native poisonous. Can be prepd by heating the ore cinnabar (HgS) either in air or with lime. Forms numerous salts, some of which are very expl, eg, Hg fulminate, Hg azide, etc. The presence of Hg in expls, even in minute quants, is unde-sireable because it affects the result of thermal stability tests. Marshall (Ref 1) describes various tests used in Engl and Ger for its detection in different expls and propints Refs 1) Marshall 2, 708-12(1917) 2) Mellor... 

Sulfur is widely distributed as sulfide ores, which include galena, PbS cinnabar, HgS iron pyrite, FeS, and sphalerite, ZnS (Fig. 15.11). Because these ores are so common, sulfur is a by-product of the extraction of a number of metals, especially copper. Sulfur is also found as deposits of the native element (called brimstone), which are formed by bacterial action on H,S. The low melting point of sulfur (115°C) is utilized in the Frasch process, in which superheated water is used to melt solid sulfur underground and compressed air pushes the resulting slurry to the surface. Sulfur is also commonly found in petroleum, and extracting it chemically has been made inexpensive and safe by the use of heterogeneous catalysts, particularly zeolites (see Section 13.14). One method used to remove sulfur in the form of H2S from petroleum and natural gas is the Claus process, in which some of the H2S is first oxidized to sulfur dioxide ... 

In cinnabar, HgS, the sulfur atom has a normal-valence structure, in which it forms two bonds with mercury atoms. The Hg—S—Hg bond angle is 105°. The mercury atom may be described as forming two oppositely directed bonds with use of two sp hybrid bond orbitals the value of the S—Hg—S angle is 172°. The bond length, 2.36 A, leads,... 

Thus, both elemental mercury and the mineral form cinnabar (HgS) can release Hg++, the mercuric ion. Bacteria can then methylate it to form sequentially CH3 Hg+, the methyl mercuric cation, and dimethyl mercury. The latter, like elemental mercury, is volatile and tends to pass into the atmosphere when formed. The methylation of mercury can be accomplished in the environment by bacteria, notably in sediments. 

Zinc and mercury are found in the Earth s crust as suifide ores, the most common of which are sphaierite (ZnS) and cinnabar (HgS). See the previous section for descriptions of the extraction and purification of these metais. 

Romans mined the mineral cinnabar (HgS) from deposits in Spain 2000 years ago, and in the sixteenth century the Spanish shipped mercury obtained from the same ore deposits to the Americas for the extraction of silver. Mercury is an important component of street lamps and fluorescent lights. It is used in thermometers and barometers and in gas-pressure regulators, electrical switches, and electrodes. 

C21-0078. The only important ore of mercury is cinnabar, HgS. In contrast, zinc is found in several ores, including sulfides, carbonates, silicates, and oxides. Explain these observations in terms of hard and soft acids and bases. 

Mercury has been known since ancient times. As early as in the 7th Century B.C., Assyrian medics applied it to cure skin diseases. Mercury compounds were also used by Arabs in the 6th Century B.C. for therapeutic reasons. Mercury was mentioned by Aristotle and Hippocrates (the 4th Century B.C.) who described cinnabar (HgS) as a dye. Mercury and its compounds have also... 

Mercury occurs in soils predominantly in the +2 oxidation state. Elemental Hg in the atmosphere is oxidized to Hg + and deposited in rainfall. It is a strong chalcophile and under anaerobic conditions forms the extremely insoluble sulfide cinnabar (HgS, pK = 52.7). Nonetheless it is not entirely immobilized under anaerobic conditions because it is reduced to volatile Hg° or methylated to volatile methyl mercury compounds by microbial action, and so returned to the atmosphere. The methylation is mediated by various bacteria, especially methanogens, through the reactions ... 

Mercury is the 68th most abundant element. Although it can occur in its natural state, it is more commonly found as a sulfide of mercury. Its chief ore is cinnabar (HgS), which sometimes is called vermihon due to its red color. Historically, cinnabar was used as a red pigment. Today it is mined in Italy, Spain, and California. The best-known mercury mine is located at Almaden, Spain. It has been in continuous operation since 400 bce. 

Today, just about all mercury is produced via the reduction of cinnabar (HgS) by using a reducing agent, such as oxygen, iron, or calcium oxide (CaO). The resulting mercury vapor is passed through water where it liquefies (changes into its normal metallic state and sinks to the bottom of the water bath) while all the impurities float to the surface. 

Sulfur is an element found in many common minerals, such as galena (PbS), pyrite (fool s gold, FeSj), sphalerite (ZnS), cinnabar (HgS), and celestite (SrSO ), among others. About 1/4 of all sulfur procured today is recovered from petroleum production. The majority of sulfur is the result of or a by-product of mining other minerals from the ores containing sulfur. 

X-ray diffraction showed that the deposit (both as a film and the precipitated material) was cinnabar HgS. The diffraction peaks were sharp (crystal size at least 20 nm, possibly much greater). 

We described elsewhere the Hg(0) vapor sorption of commercial CuS [10]. The relative rate of Hg(0) uptake for commercial grade cuS is 12.8 mmoles/day compared with 70 mmoles/day for CTAB mediated CuS. The sorption properties of the particle-size-mediated synthesized covellite, CuS, is likewise reflective of a redox process that results in the formation of cinnabar, HgS, and the copper(I) sulfide chalcocite, CU2S, according to Reaction (1) ... 

Sulfur is widely distributed as sulfide ores, which include galena, PbS cinnabar, HgS iron pyrite, FeS2 and sphalerite, ZnS (Fig. 15.12). The mineral molybdenite, MoS2, is a soft rock with a metallic sheen and properties similar to those of graphite. Sulfur is also found as deposits of the native element (called brimstone), which are formed by bacterial action on H2S. 

Metallic mercury is obtained by heating the mineral cinnabar (HgS) in air ... 

T FIGURE 21.1 Samples of (a) hematite (Fe203), (b) starshaped needles of rutile (Ti02) on a quartz matrix, and (c) cinnabar (HgS). 

Most metals occur in nature as minerals, the crystalline, inorganic constituents of the rocks that make up the earth s crust. Silicates and aluminosilicates (Section 19.7) are the most abundant minerals, but they are difficult to concentrate and reduce and are therefore generally unimportant as commercial sources of metals. More important are oxides and sulfides, such as hematite (Fe203), rutile (Ti02), and cinnabar (HgS) (Figure 21.1), which yield iron, titanium, and... 

Gold and platinum are so inactive that they are usually found in nature in uncombined form, but copper and silver, which are slightly more active, are found in both combined and uncombined form. Copper, silver, and mercury commonly occur in sulfide ores that are easily reduced by roasting. Cinnabar (HgS), for example, yields elemental mercury when the ore is heated at 600°C in a stream of air ... 

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