| IUPAC name
| Other names
|Molar mass||232.66 g/mol|
|Appearance|| Red solid (α-HgS)|
Black solid (β-HgS)
|Melting point||580 °C (1,076 °F; 853 K) (decomposes)|
|Solubility||Insoluble in organic solvents|
|Vapor pressure||~0 mmHg|
Std enthalpy of
|Safety data sheet||Sigma-Aldrich|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Mercury sulfide, also known as mercury(II) sulfide or mercuric sulfide is a chemical compound composed with the formula HgS. It occurs naturally as the mineral cinnabar .
Mercury sulfide is resistant to the attack of most reagents, such as acids and bases.
It will however react with oxidizing mixtures at high temperatures, such as acidified dichromate solutions in conc. sulfuric acid, at temperatures above 100-150 °C.
However, mercury sulfide in cinnabar form will burn when ignited in air or a stream of pure oxygen, releasing sulfur dioxide and mercury vapors, which are very toxic and corrosive to many metals, like aluminium.
- HgS + O2 → Hg + SO2
Mercury sulfide is a red or black solid, virtually insoluble in water and all solvents. The black form is the beta-polymorph (cubic structure) while the red form is the alpha-polymorph (hexagonal structure). The two forms can be interconverted, for example the red form is transformed into the red form by extended heating in a polysulfide solution.
Cinnabar can be purchased from various mineral suppliers. In some countries its sale may be regulated.
Mercury(II) sulfide can be created by adding elemental sulfur to mercury metal. Zinc powder is sometimes added to accelerate the reaction. Mercury sulfide is the main product of mercury disposal, as it is inert and safe to handle.
By precipitating mercury salts with hydrogen sulfide or soluble sulfides usually the black polymorph is obtained. Heating in polysulfide solutions convert it into the red polymorph.
- Mineral collecting
- Make elemental mercury (VERY DANGEROUS)
Cinnabar is toxic and should be handled with proper protection.
In closed containers.
Should be take to disposal centers.
- E. H. Pietsch et al., Gmelins Handbuch der anorganischen Chemie, Quecksilber Teil B Lieferung 3, 8th edition, 1968, Verlag Chemie GmbH, Weinheim/Bergstr., p. 954-967