Mercury sulfide

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Mercury sulfide
HgS-alpha-cinnabar-xtal-1999-looking-down-a-axis-CM-3D-balls.png
HgS-alpha-cinnabar-xtal-1999-looking-down-c-axis-CM-3D-balls.png
Identifiers
CAS number 1344-48-5 YesY
PubChem 62402
Properties
Molecular formula HgS
Molar mass 232.66 g/mol
Density 8.10 g/cm3
Melting point 580 °C (1,076 °F; 853 K) decomposes
Solubility in water insoluble
Band gap 2.1 eV (direct, α-HgS) [1]
Refractive index (nD) w=2.905, e=3.256, bire=0.3510 (α-HgS) [2]
Thermochemistry
Std molar
entropy
So298
78 J·mol−1·K−1[3]
Std enthalpy of
formation
ΔfHo298
−58 kJ·mol−1[3]
Hazards
MSDS ICSC 0981
EU Index 080-002-00-6
EU classification Very toxic (T+)
Dangerous for the environment (N)
R-phrases R26/27/28, R33, R50/53
S-phrases (S1/2), S13, S28, S45, S60, S61
Flash point Non-flammable
Related compounds
Other anions Mercury oxide
Mercury selenide
Mercury telluride
Other cations Zinc sulfide
Cadmium sulfide
Except where noted otherwise, 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[edit]

Cinnabar from Nevada, USA

HgS is dimorphic with two crystal forms:

Crystals of red, α-HgS, are optically active. This is caused by the Hg-S helices in the structure.[5]

Preparation and chemistry[edit]

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[edit]

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.[7]

See also[edit]

References[edit]

  1. ^ L. I. Berger, Semiconductor Materials (1997) CRC Press ISBN 0-8493-8912-7
  2. ^ Webminerals
  3. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN 0-618-94690-X. 
  4. ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 1406. ISBN 0-08-022057-6. 
  5. ^ Glazer, A. M.; Stadnicka K. (1986). "On the origin of optical activity in crystal structures". J. Appl. Cryst. 19 (2): 108–122. doi:10.1107/S0021889886089823. 
  6. ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5 
  7. ^ Cotte, M; 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:10.1021/ac0612224. PMID 17073416.