Chromium(II) sulfide

Chromium(II) sulfide is an inorganic compound of chromium and sulfur with the chemical formula CrS.^[1][2][3] The compound forms black hexagonal crystals, insoluble in water.^[4]

Chromium(II) sulfide

Identifiers
CAS Number	12018-06-3
3D model (JSmol)	Interactive image
ChemSpider	10129648
PubChem CID	11955372
CompTox Dashboard (EPA)	DTXSID10923256
InChI InChI=1S/Cr.S/q+2;-2 Key: LXEAUGDQDABWTN-UHFFFAOYSA-N
SMILES [S-2].[Cr+2]
Properties
Chemical formula	CrS
Molar mass	84.061 g/mol
Appearance	Black crystals
Melting point	1,550 °C (2,820 °F; 1,820 K)
Solubility in water	Insoluble
Related compounds
Related compounds	Chromium(III) sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Chromium(II) sulfide may be formed by reaction of chromium metal with sulfur or hydrogen sulfide at high temperature. It may also be formed by reacting chromium(III) chloride with H₂S, reducing chromium(III) sulfide with hydrogen, or by double replacement reaction of lithium sulfide with chromium(II) chloride.^[5]

Cr + S → CrS

Cr + H₂S → CrS + H₂

2 CrCl₃ + 3 H₂S → 2 CrS + S + 6 HCl

Cr₂S₃ + H₂ → 2 CrS + H₂S

Li₂S + CrCl₂ → 2 LiCl + CrS

Physical properties

Chromium(II) sulfide forms black paramagnetic crystals of two crystalline modifications:^[6]

• 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,^[7][8] and is also used as a catalyst.^[9]

Chemical properties

Chromium(II) sulfide slowly oxidizes in air:^{[citation needed]}

2 CrS + 7 O₂ → 2 Cr₂O₃ + 4 SO₂