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
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 (ΔfH⦵298)
 −58 kJ·mol−1[3]
Hazards
Safety data sheet (SDS) ICSC 0981
GHS labelling:
GHS06: ToxicGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Signal word
 Warning
H300, H310, H317, H330, H373, H410
P261, P272, P280, P302+P352, P321, P333+P313, P363, P501
NFPA 704 (fire diamond)
3
1
0
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).
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Infobox references

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[]

Cinnabar from Nevada, US

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. Cinnabar has rhombohedral crystal system. Crystals of red are optically active. This is caused by the Hg-S helices in the structure.[5]
  • black, metacinnabar (β-HgS), is less common in nature and adopts the zinc blende (T2d-F43m) crystal structure.

Preparation and chemistry[]

β-HgS precipitates as a black solid when Hg(II) salts are treated with H2S. The reaction is conveniently conducted with an acetic acid solution of mercuric acetate. With gentle heating of the slurry, the black 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[]

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.

See also[]

References[]

  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 978-0-618-94690-7.
  4. ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 1406. ISBN 978-0-08-022057-4.
  5. ^ A. M. Glazer, K. Stadnicka (1986). "On the origin of optical activity in crystal structures". J. Appl. Cryst. 19 (2): 108–122. doi:10.1107/S0021889886089823.
  6. ^ Newell, Lyman C.; Maxson, R. N.; Filson, M. H. (1939). "Red Mercuric Sulfide". Inorganic Syntheses. Inorganic Syntheses. 1. pp. 19–20. doi:10.1002/9780470132326.ch7. ISBN 9780470132326.
  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.
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