Mercury sulfide
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| Names | |
|---|---|
| IUPAC name
Mercury sulfide
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| Other names | |
| Identifiers | |
1344-48-5  |
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| PubChem | 62402 |
| Properties | |
| HgS | |
| Molar mass | 232.66 g/mol |
| Density | 8.10 g/cm3 |
| Melting point | 580 °C (1,076 °F; 853 K) decomposes |
| insoluble | |
| Band gap | 2.1 eV (direct, α-HgS) [1] |
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Refractive index (nD)
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w=2.905, e=3.256, bire=0.3510 (α-HgS) [2] |
| Thermochemistry | |
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Std molar
entropy (S |
78 J·mol−1·K−1[3] |
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Std enthalpy of
formation (ΔfH |
−58 kJ·mol−1[3] |
| Vapor pressure | {{{value}}} |
| Related compounds | |
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Other anions
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Mercury oxide Mercury selenide Mercury telluride |
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Other cations
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Zinc sulfide Cadmium sulfide |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |
Mercury sulfide, mercuric sulfide, mercury sulphide, 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.[4]
Crystal structure
HgS is dimorphic with two crystal forms:
- red cinnabar (α-HgS, trigonal, hP6, P3221), is the form in which mercury is most commonly found in nature.
- black, metacinnabar (β-HgS), is less common in nature and adopts the zinc blende (T2d-F43m) crystal structure.
Crystals of red, α-HgS, are optically active. This is caused by the Hg-S helices in the structure.[5]
Preparation and chemistry
β-HgS is precipitated as a black powder when H2S is bubbled through solutions of Hg(II) salts.[6] β-HgS is unreactive to all but concentrated acids.[4]
Mercury metal is produced from the cinnabar ore by roasting in air and condensing the vapour.[4]
Uses
When α-HgS is used as a red pigment, it is known as vermilion. The tendency of vermilion to darken has been ascribed to conversion from red α-HgS to black β-HgS. However β-HgS was not detected at excavations in Pompeii, where originally red walls darkened, and was attributed to the formation of Hg-Cl compounds (e.g., corderoite, calomel, and terlinguaite) and calcium sulfate, gypsum.[7]
See also
References
- ↑ L. I. Berger, Semiconductor Materials (1997) CRC Press ISBN 0-8493-8912-7
- ↑ Webminerals
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