Mercury sulfide

• Cinnabar
• Mercury (II ) sulfide

Odorless, red crystals

Fixed

8.18 g · cm -3

386 ° C

584 ° C

Practically insoluble in water

Attention

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

Production and representation

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

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

Modifications

All three modifications occur in nature as minerals, but can be produced synthetically.

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

The cubic crystalline Metacinnabarit, also known as mercury Mohr, is the black modification. It occurs when a mercury salt solution hydrogen sulphide is added. For better handling, you can create hydrogen sulfide directly in the reaction solution of thioacetamide by heating in an alkaline medium.

The third modification is the hexagonally crystallized Hypercinnabarit.

Use

Mercury sulfide is used as a red pigment ( vermilion ). Due to its extremely high solubility - the solubility of HgS in water is approximately 10-54 mol2 · l -2 ​​- it's unlike almost all other mercury compounds, non-toxic.