Chromium(II) sulfide is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

chromium Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. Chromium metal is valued for its high corrosion resistance and hardne ...

and

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

with the chemical formula CrS. The compound forms black hexagonal crystals, insoluble in water.

Synthesis

Chromium(II) sulfide may be formed by reaction of chromium metal with sulfur or

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

at high temperature. It may also be formed by reacting chromium(III) chloride with H₂S, reducing

chromium(III) sulfide Chromium(III) sulfide is the inorganic compound with the formula chromium, Cr2sulfide, S3. It is a brown-black solid. Chromium sulfides are usually nonstoichiometric compounds, with formulas ranging from CrS to Cr0.67S (corresponding to Cr2S3). P ...

with hydrogen, or by

double replacement reaction A salt metathesis reaction, sometimes called a double displacement reaction, is a chemical process involving the exchange of chemical bond, bonds between two reacting chemical species which results in the creation of products with similar or ident ...

of lithium sulfide with chromium(II) chloride. ::Cr + S -> CrS ::Cr + H2S -> CrS + H2 ::2CrCl3 + 3H2S -> 2CrS + S + 6HCl ::Cr2S3 + H2 -> 2CrS + H2S ::Li2S + CrCl2 -> 2LiCl + CrS

Physical properties

Chromium(II) sulfide forms black paramagnetic crystals of two crystalline modifications: *α-CrS, superstructured phase, hexagonal system, cell parameters a = 1.200 nm, c = 1.152 nm. *β-CrS, monoclinic system, cell parameters a = 0.594 nm, b = 0.341 nm, c = 0.563 nm, β = 91.73°. Chromium(II) sulfide is a semiconductor, and is also used as a catalyst.

Chemical properties

Chromium(II) sulfide slowly oxidizes in air: ::2CrS + 7O2 -> 2Cr2O3 + 4SO2

References

{{Chromium compounds Chromium(II) compounds Sulfides