Copper(II) oxide

Copper(II) oxide

Names
IUPAC name Copper(II) oxide
Other names Cupric oxide
Identifiers
CAS Number	1317-38-0 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:75955 N
ChEMBL	ChEMBL1909057 N
ChemSpider	144499 Y
ECHA InfoCard	100.013.882
PubChem	14829
RTECS number	GL7900000
UNII	V1XJQ704R4 Y
InChI InChI=1S/Cu.O/q+2;-2 Y Key: KKCXRELNMOYFLS-UHFFFAOYSA-N Y InChI=1/Cu.O/rCuO/c1-2 Key: QPLDLSVMHZLSFG-PHEGLCPBAN InChI=1/Cu.O/q+2;-2 Key: KKCXRELNMOYFLS-UHFFFAOYAT
SMILES [Cu]=O [Cu+2].[O-2]
Properties
Chemical formula	CuO
Molar mass	79.545 g/mol
Appearance	black to brown powder
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)
Solubility in water	insoluble
Solubility	soluble in ammonium chloride, potassium cyanide insoluble in alcohol, ammonium hydroxide, ammonium carbonate
Band gap	1.2 eV
Magnetic susceptibility (χ)	+238.9·10−6 cm3/mol
Refractive index (nD)	2.63
Structure
Crystal structure	monoclinic, mS8
Space group	C2/c, #15
Lattice constant	a = 4.6837, b = 3.4226, c = 5.1288 α = 90°, β = 99.54°, γ = 90°
Thermochemistry
Std molar entropy (So298)	43 J·mol−1·K−1
Std enthalpy of formation (ΔfHo298)	−156 kJ·mol−1
Hazards
Safety data sheet	Fischer Scientific
EU classification (DSD)	Harmful (Xn) Dangerous for the environment (N)
NFPA 704	0 2 1
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(II) sulfide
Other cations	Nickel(II) oxide Zinc oxide
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).
N  (what is YN ?)
Infobox references

Copper(II) oxide or cupric oxide is the inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu₂O or cuprous oxide. As a mineral, it is known as tenorite and paramelaconite. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.

It is produced on a large scale by pyrometallurgy used to extract copper from ores. The ores are treated with an aqueous mixture of ammonium carbonate, ammonia, and oxygen to give copper(I) and copper(II) ammine complexes, which are extracted from the solids. These complexes are decomposed with steam to give CuO.

It can be formed by heating copper in air at around 300 - 800°C:

For laboratory uses, pure copper(II) oxide is better prepared by heating copper(II) nitrate, copper(II) hydroxide or copper(II) carbonate:

Copper(II) oxide is an amphoteric oxide, so it dissolves in mineral acids such as hydrochloric acid, sulfuric acid or nitric acid to give the corresponding copper(II) salts:

It reacts with concentrated alkali to form the corresponding cuprate salts:

It can also be reduced to copper metal using hydrogen, carbon monoxide, or carbon:

When cupric oxide is substituted for iron oxide in thermite the resulting mixture is a low explosive, not an incendiary.

Copper(II) oxide belongs to the monoclinic crystal system. The copper atom is coordinated by 4 oxygen atoms in an approximately square planar configuration.