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| Mercury sulfide | |
|---|---|
 |
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| Other names | cinnabar, vermillion |
| Identifiers | |
| CAS number | [1344-48-5] |
| Properties | |
| Molecular formula | HgS |
| Molar mass | 232.66 g mol−1 |
| Density | 8.10 g cm−3 |
| Melting point |
583.5°C |
| Boiling point |
N/A |
| Solubility in other solvents | insoluble |
| Hazards | |
| R-phrases | R21, R26, R28 |
| Related compounds | |
| Other anions | Mercury selenide; Mercury telluride; Cadmium sulfide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Mercury sulfide, mercuric sulfide, or mercury(II) sulfide is a chemical compound composed of the chemical elements mercury and sulfur. It is represented by the chemical formula HgS. It is virtually insoluble in water. [1]. HgS is dimorphic with two crystal forms:
- red cinnabar (α-HgS), is the form in which mercury is most commonly found in nature.
- black, metacinnabar (β-HgS), is less common in nature and adopts the wurtzite crystal structure.
Crystals of red, α-HgS, are optically active. This is caused by the helices of Hg-S in the structure.[2]
α-HgS is a direct semiconductor with an energy gap of 2.1eV at 300 K . [3]
Contents |
Preparation and Chemistry
β-HgS is precipitated as a black powder when H2S is bubbled through solutions of Hg(II) salts.[4] β-HgS is unreactive to all but concentrated acids.[1]
Mercury metal is produced from the cinnabar ore by roasting in air and condensing the vapour. [1]
Uses
α-HgS is used as a red pigment when it is known as vermilion. Vermilion is known to darken and this has been ascribed to conversion from red α-HgS to black β-HgS. Investigations at Pompeii where red walls when originally excavated have darkened has been ascribed to the formation of Hg-Cl compounds (e.g., corderoite, calomel, and terlinguaite) and calcium sulfate, gypsum, rather than β-HgS, which was not detected.[5]
In Alchemy
In alchemy, known as "the Sulfur of Perfection," representing the marriage of sulfur (soul) and mercury (spirit) and the "spiritual goal of alchemical work."
See also
References
- ^ a b c Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
- ^ Glazer; Stadnicka K. (April 1986). "On the origin of optical activity in crystal structures". J. Appl. Cryst. 19: 108–122. doi:.
- ^ Lev Isaakovich Berger, Semiconductor Materials (1997) CRC Press ISBN 0849389127
- ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th Edn.) New York:Wiley-Interscience. ISBN 0-471-19957-5.
- ^ Cotte; Susini J, Metrich N, Moscato A, Gratziu C, Bertagnini A, Pagano M (2006). "Blackening of Pompeian Cinnabar Paintings: X-ray Microspectroscopy Analysis". Anal. Chem. 78 (21): 7484–7492. doi:.
External links
- National Pollutant Inventory - Mercury and compounds Fact Sheet
- small article about HgS alchemical history
Wikipedia content modification information:
- This page was last modified on 30 August 2008, at 02:05.
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