Definitions

black mercuric sulfide

Mercury sulfide

| Section8 = }} Mercury sulfide, mercuric 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. . HgS is dimorphic with two crystal forms:

  • red cinnabar (α-HgS), is the form in which mercury is most commonly found in nature.
  • black, metacinnabar (β-HgS), is less common in nature and adopts the wurtzite crystal structure.

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

α-HgS is a direct semiconductor with an energy gap of 2.1eV at 300 K .

Preparation and Chemistry

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.

Uses

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.

In Alchemy

In alchemy, known as "the Sulfur of Perfection," representing the marriage of sulfur (soul) and mercury (spirit) and the "spiritual goal of alchemical work."

See also

References

External links

Search another word or see black mercuric sulfideon Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature