Copper(II) oxide

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Copper(II) oxide
Cupric oxide.JPG
IUPAC name
Copper(II) oxide
Other names
Copper brown
Copper monoxide
Cupric oxide
Molar mass 79.545 g/mol
Appearance Black solid
Odor Odorless
Density 6.315 g/cm3
Melting point 1,326 °C (2,419 °F; 1,599 K)
Boiling point 2,000 °C (3,630 °F; 2,270 K) (decomposes)
Solubility Reacts with acids
Soluble in aq. ammonia, KCN, NH4Cl
Insoluble in organic solvents
Vapor pressure ~0 mmHg
43 J·mol−1·K−1
−156 kJ/mol
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Copper(I) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Copper(II) oxide or cupric oxide (formula CuO) is a high oxide of copper. It is a black material that often coats old pieces of copper, most commonly found in pure form as a powder.



Copper(II) oxide is a black colored, ionic oxide. It is formed by oxidation of copper metal either with a chemical oxidizer, by heating in atmospheric oxygen or by electrochemical oxidation using copper as a anode. cupric oxide can be converted back to copper metal by carbothermal reduction, in which it is reduced by carbon under strong heat.


Most acids will dissolve copper(II) oxide to give their corresponding copper(II) salts.


Copper(II) oxide is most commonly used for coloring materials such as cloth and ceramic due to its deep black color. Therefore, it can be bought from pottery supply stores.


Copper salts can be precipitated with either a carbonate or hydroxide to form either copper(II) carbonate or copper(II) hydroxide. These salts can be heated to from copper(II) oxide.

Copper oxide can also be produced from electrolysis using a copper anode and a dilute solution of hydroxide dissolved in water. This product should be heated at over 200°C to decompose hydroxide impurities.[1]


  • Explosive thermite
  • Flash powder
  • Producing the energetic bis(ethylenediamine)copper(II) perchlorate
  • Producing other copper salts



Copper(II) oxide is an irritant, so avoid handling it directly. Since it is insoluble, it can be disposed of as toxic waste without alteration. It will also stain many materials, though it's relative easy to clean, by dissolving it in a weak acid, such as acetic acid.


Copper(II) oxide should be stored in closed bottles, away from moisture and acidic vapors.


As it is toxic, copper oxide should be reduced to copper metal and recycled.



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