Names | |
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IUPAC name
Copper(I) sulfide
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Other names | |
Identifiers | |
3D model (JSmol)
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ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.040.751 |
PubChem CID
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RTECS number |
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
Cu2S | |
Molar mass | 159.16 g/mol |
Density | 5.6 g/cm3 [1] |
Melting point | 1,130 °C (2,070 °F; 1,400 K)[2] |
Insoluble | |
Solubility | slightly soluble in HCl; soluble in NH4OH; dissolves in KCN; decomposes in HNO3, H2SO4 |
Hazards | |
Flash point | Non-flammable |
NIOSH (US health exposure limits): | |
PEL (Permissible)
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TWA 1 mg/m3 (as Cu)[3] |
REL (Recommended)
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TWA 1 mg/m3 (as Cu)[3] |
IDLH (Immediate danger)
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TWA 100 mg/m3 (as Cu)[3] |
Related compounds | |
Other anions
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Copper(I) oxide Copper(I) selenide |
Other cations
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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).
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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 Cu1.997S to Cu2.000S.[4]
Cu2S can be prepared by heating copper strongly in sulfur vapour or H2S.[2] The reaction of copper powder in molten sulfur rapidly produces Cu2S, whereas pellets of copper require much higher temperature.[5] Cu2S reacts with oxygen to form SO2:[6]
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:[6]
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[7] and a hexagonal form stable above 104 °C.[8] 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 Cu1.96S which is non-stoichiometric (range Cu1.934S-Cu1.965S) and has a monoclinic structure with 248 copper and 128 sulfur atoms in the unit cell.[7] Cu2S and Cu1.96S are similar in appearance and hard to distinguish one from another.[9]