Mercury sulfide

Crystal structure
Hg 2+ : __   / S 2− : __
General
Surname	Mercury sulfide
other names	cinnabar Mercury (II) sulfide
Ratio formula	HgS
Brief description	odorless, red crystals
External identifiers / databases
CAS number 1344-48-5 EC number 215-696-3 ECHA InfoCard 100.014.270 PubChem 62402 Wikidata Q179518
properties
Molar mass	232.65 g mol −1
Physical state	firmly
density	8.1 g cm −3
Melting point	386 ° C
boiling point	584 ° C
solubility	practically insoluble in water
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 317 EUH: 031 P: 280
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Mercury sulfide (HgS) is a chemical compound made from mercury and sulfur . It belongs to the group of II-VI compound semiconductors and exists in three modifications .

Extraction and presentation

The black modification can be obtained by reacting an aqueous solution of mercury (II) chloride with additions of EDTA and ammonium nitrate with hydrogen sulfide and ammonia .

${\displaystyle \mathrm {HgCl_{2}+H_{2}S+2\ NH_{3}\longrightarrow HgS+2\ NH_{4}Cl} }$

The red modification can be obtained by reacting mercury (II) acetate with hydrogen sulfide in hot glacial acetic acid.

${\displaystyle \mathrm {Hg(CH_{3}COO)_{2}+H_{2}S\longrightarrow HgS+2\ CH_{3}COOH} }$

Modifications

Mercury sulfide (cinnabarite) as a pigment cinnabar red

All three modifications occur naturally as minerals , but can also be produced synthetically.

The trigonal modification cinnabarite is also commonly known as cinnabar and namesake of the color vermilion .

The cubic crystallizing metacinnabar , also known as mercury black, is the black modification. It occurs when hydrogen sulfide is added to a mercury salt solution. Because of the better handling, hydrogen sulfide can be generated directly in the reaction solution of thioacetamide by heating in an alkaline medium.

The third modification is the hexagonal crystallizing hypercinnabarite .

use

Mercury sulfide is used as a red pigment (vermilion). Due to its extremely high solubility - the solubility product for HgS in water is approx. 10 ⁻⁵⁴ mol ² · l ⁻² - it is, in contrast to almost all other mercury compounds, non-toxic.

Elemental mercury can be converted with sulfur into the red modification of mercury sulfide and in principle be stored underground for disposal .

Individual evidence

1. ↑ ^{a b c d e f} entry to mercury (II) sulfide in the GESTIS database of IFA , retrieved on February 1, 2016(JavaScript required) .
2. ↑ Entry on mercury (II) sulfide. In: Römpp Online . Georg Thieme Verlag, accessed on December 2, 2016.
3. ↑ ^{a b} Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 1054.
4. ↑ Entry on cinnabarite. In: Römpp Online . Georg Thieme Verlag, accessed on June 18, 2014.
5. ^ Uni Bielefeld: Solubility of Salts , accessed on November 22, 2007.
6. ↑ Federal Environment Agency: Behavior of mercury and mercury compounds in the case of underground storage in salt formations, in particular their possible mobilization through saline solutions
7. ↑ Federal Ministry for Economic Affairs and Energy: Safe disposal of liquid mercury by converting it into non-toxic mercury sulfide