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Mercuric sulfide

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
Names
IUPAC name
Mercury sulfide
Other names
Identifiers
1344-48-5 YesY
ECHA InfoCard 100.014.270
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)
−55.4·10−6 cm3/mol
w=2.905, e=3.256, bire=0.3510 (α-HgS)
Thermochemistry
78 J·mol−1·K−1
−58 kJ·mol−1
Hazards
Safety data sheet ICSC 0981
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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
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.

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.

β-HgS is precipitated as a black powder when H2S is bubbled through solutions of Hg(II) salts. β-HgS is unreactive to all but concentrated acids.
Mercury metal is produced from the cinnabar ore by roasting in air and condensing the vapour.

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.



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