Copper(I) sulfide is a
copper sulfide
Copper sulfides describe a family of chemical compounds and minerals with the formula CuxSy. Both minerals and synthetic materials comprise these compounds. Some copper sulfides are economically important ores.
Prominent copper sulfide mineral ...
, a chemical compound of
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
and
sulfur. It has the chemical compound Cu
2S. It is found in nature as the mineral
chalcocite
Chalcocite (), copper(I) sulfide (Cu2S), is an important copper ore mineral. It is opaque and dark gray to black, with a metallic luster. It has a hardness of 2.5–3 on the Mohs scale. It is a sulfide with a monoclinic crystal system.
...
. It has a narrow range of stoichiometry ranging from Cu
1.997S to Cu
2.000S.
Preparation and reactions
Cu
2S can be prepared by heating copper strongly in sulfur vapour or H
2S.
The reaction of copper powder in molten sulfur rapidly produces Cu
2S, whereas pellets of copper require much higher temperature.
Cu
2S reacts with oxygen to form SO
2:
[Wiberg, Egon and Holleman, Arnold Frederick (2001) ''Inorganic Chemistry'', Elsevier ]
:2 Cu
2S + 3 O
2 → 2 Cu
2O + 2 SO
2
In the production of copper two thirds of the molten copper sulfide is oxidised as above, and the Cu
2O reacts with unoxidised Cu
2S to give Cu metal:
: Cu
2S + 2 Cu
2O → 6 Cu + SO
2
Structure
There are two forms of Cu
2S: 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.
[Wells A.F. (1984) ''Structural Inorganic Chemistry'', 5th ed., Oxford Science Publications, ] 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
Djurleite is a copper sulfide mineral of secondary origin with formula Cu31S16 that crystallizes with monoclinic-prismatic symmetry. It is typically massive in form, but does at times develop thin tabular to prismatic crystals. It occurs with oth ...
) with stoichiometry Cu
1.96S which is
non-stoichiometric
In chemistry, non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); m ...
(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 Cu1.96S are similar in appearance and hard to distinguish one from another.]
See also
*Copper sulfide
Copper sulfides describe a family of chemical compounds and minerals with the formula CuxSy. Both minerals and synthetic materials comprise these compounds. Some copper sulfides are economically important ores.
Prominent copper sulfide mineral ...
for an overview of all copper sulfide phases
*Copper monosulfide
Copper monosulfide is a chemical compound of copper and sulfur. It was initially thought to occur in nature as the dark indigo blue mineral covellite. However, it was later shown to be rather a cuprous compound, formula Cu+3S(S2).Liang, W., Whan ...
, CuS
*Chalcocite
Chalcocite (), copper(I) sulfide (Cu2S), is an important copper ore mineral. It is opaque and dark gray to black, with a metallic luster. It has a hardness of 2.5–3 on the Mohs scale. It is a sulfide with a monoclinic crystal system.
...
*Djurleite
Djurleite is a copper sulfide mineral of secondary origin with formula Cu31S16 that crystallizes with monoclinic-prismatic symmetry. It is typically massive in form, but does at times develop thin tabular to prismatic crystals. It occurs with oth ...
References
{{Sulfides
Sulfide minerals
Sulfides
Copper(I) compounds
Non-stoichiometric compounds
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