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| Names | |
|---|---|
| IUPAC name Copper(I) sulfide | |
| Other names | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.040.751 |
| RTECS number |
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| UNII | |
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| Properties | |
| Cu2S | |
| Molar mass | 159.16 g/mol |
| Density | 5.6 g/cm3[1][page needed] |
| Melting point | 1,130 °C (2,070 °F; 1,400 K)[2] |
| insoluble[citation needed] | |
| Solubility inhydrochloric acid | slightly soluble[citation needed][quantify] |
| Solubility inammonium hydroxide | soluble[citation needed][quantify] |
| Hazards[4] | |
| NFPA 704 (fire diamond) | |
| Flash point | Nonflammable |
| NIOSH (US health exposure limits):[5] | |
PEL (Permissible) | TWA1 mg/m3 (as Cu) |
REL (Recommended) | TWA1 mg/m3 (as Cu) |
IDLH (Immediate danger) | TWA100 mg/m3 (as Cu) |
| Safety data sheet (SDS) | Sigma-Aldrich[3] |
| Related compounds | |
Otheranions | |
Othercations | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Copper(I) sulfide is acopper sulfide, a chemical compound ofcopper andsulfur. It has thechemical formula ofCu2S. It is found in nature as the mineralchalcocite. It has a narrow range of stoichiometry ranging fromCu1.997S toCu2.000S.[6] Samples are typically black.[citation needed]
Cu2S can be prepared by treating copper with sulfur orH2S.[2] The rate depends on the particle size and temperature.[7]Cu2S reacts with oxygen to formSO2:[8][page needed]
The production of copper from chalcocite is a typical process in extracting the metal from ores. Usually, the conversion involves roasting, to giveCu2O as an intermediate which is further reduced to the metal, and sulfur dioxide:[8][page needed]
Copper(I) oxide readily converts tocopper(II) oxide when heated in the presence of oxygen, and to copper metal upon heating in a reducing environment. (cf.Carbothermic reduction)
Two forms (a dimorphism) ofCu2S are known. The so-called low temperaturemonoclinic form ("low-chalcocite") has a complex structure with 96 copper atoms in the unit cell.[9] The hexagonal form, stable above 104 °C (219 °F),[10][page needed] has 24 crystallographically distinct Cu atoms. Its structure has been described as approximating to ahexagonal 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.
As illustrated by the mineraldjurleite, a cuprous sulfide is also known.[clarification needed] With the approximate formulaCu1.96S, this material isnon-stoichiometric (rangeCu1.934S-Cu1.965S and has a monoclinic structure with 248 copper and 128 sulfur atoms in the unit cell.[9]Cu2S andCu1.96S are similar in appearance and hard to distinguish one from another.[11]
Theelectrical resistivity increases abruptly at the phase transition point around 104 °C (219 °F), with the precise temperature depending on the stoichiometry.[12][13]
