Mercury sulfide

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Mercury sulfide
Names
IUPAC name
Mercury sulfide
Other names
Identifiers
3D model (
JSmol
)
ECHA InfoCard
100.014.270 Edit this at Wikidata
EC Number
  • 215-696-3
UNII
UN number 2025
  • InChI=1S/Hg.S
    Key: QXKXDIKCIPXUPL-UHFFFAOYSA-N
  • [S]=[Hg]
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]
−55.4·10−6 cm3/mol
w=2.905, e=3.256, bire=0.3510 (α-HgS) [2]
Thermochemistry
78 J·mol−1·K−1[3]
Std enthalpy of
formation
fH298)
−58 kJ·mol−1[3]
Hazards
GHS labelling:
GHS06: ToxicGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Danger
H300, H310, H317, H330, H373, H410
P261, P272, P280, P302+P352, P321, P333+P313, P363, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
4
0
0
Flash point Non-flammable
Safety data sheet (SDS) Fisher Scientific
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).
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Mercury 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.[4]

Crystal structure

Structure of a-HgS looking at the a-axis
Structure of a-HgS looking at the c-axis

HgS is dimorphic with two crystal forms:

Preparation and chemistry

β-HgS precipitates as a black solid when Hg(II) salts are treated with

polymorph converts to the red form.[6] β-HgS is unreactive to all but concentrated acids.[4]

Mercury is produced from the cinnabar ore by roasting in air and condensing the vapour.[4]

HgS → Hg + S

Uses

Cinnabar (red portion of specimen) from Nevada, US.

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]

As the mercury cell as used in the chlor-alkali industry (Castner–Kellner process) is being phased out over concerns over mercury emissions, the metallic mercury from these setups is converted into mercury sulfide for underground storage.

With a band gap of 2.1 eV and its stability, it is possible to be used as photoelectrochemical cell.[8]

See also

References