Copper(I) sulfide

Copper(I) sulfide

Names
IUPAC name Copper(I) sulfide
Other names Cuprous sulfide Chalcocite Copper glance
Identifiers
CAS Number	22205-45-4 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:51114 Y
ChemSpider	8305611 Y
ECHA InfoCard	100.040.751
PubChem	62755
RTECS number	GL8910000
InChI InChI=1S/2Cu.S/q2*+1;-2 Y Key: AQMRBJNRFUQADD-UHFFFAOYSA-N Y InChI=1/2Cu.S/q2*+1;-2 Key: AQMRBJNRFUQADD-UHFFFAOYAN
SMILES [Cu+].[Cu+].[S-2]
Properties
Chemical formula	Cu2S
Molar mass	159.16 g/mol
Density	5.6 g/cm3
Melting point	1,130 °C (2,070 °F; 1,400 K)
Solubility in water	Insoluble
Solubility	slightly soluble in HCl; soluble in NH4OH; dissolves in KCN; decomposes in HNO3, H2SO4
Hazards
Flash point	Non-flammable
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 1 mg/m3 (as Cu)
REL (Recommended)	TWA 1 mg/m3 (as Cu)
IDLH (Immediate danger)	TWA 100 mg/m3 (as Cu)
Related compounds
Other anions	Copper(I) oxide Copper(I) selenide
Other cations	Nickel(II) sulfide Copper(II) sulfide Zinc sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Copper(I) sulfide is a copper sulfide, a chemical compound of copper and sulfur. It has the chemical compound Cu₂S. It is found in nature as the mineral chalcocite. It has a narrow range of stoichiometry ranging from Cu_1.997S to Cu_2.000S.

Cu₂S can be prepared by heating copper strongly in sulfur vapour or H₂S. The reaction of copper powder in molten sulfur rapidly produces Cu₂S, where as pellets of copper require much higher temperature. Cu₂S reacts with oxygen to form SO₂:

In the production of copper two thirds of the molten copper sulfide is oxidised as above, and the Cu₂O reacts with unoxidised Cu₂S to give Cu metal:

There are two forms of Cu₂S a low temperature monoclinic form ("low-chalcocite") which has a complex structure with 96 copper atoms in the unit cell and a hexagonal form stable above 104 °C. In this structure there are 24 crystallographically distinct Cu atoms and the structure has been described as approximating to a hexagonal close packed array of sulfur atoms with Cu atoms in planar 3 coordination. This structure was initially assigned an orthorhombic cell due to the twinning of the sample crystal.

There is also a crystallographically-distinct phase (the mineral djurleite) with stoichiometry Cu_1.96S which is non-stoichiometric (range Cu_1.934S-Cu_1.965S) and has a monoclinic structure with 248 copper and 128 sulfur atoms in the unit cell. Cu₂S and Cu_1.96S are similar in appearance and hard to distinguish one from another.