copper(II) oxide

Black solid that is readily reduced to copper by carbon, carbon monoxide, or hydrogen if heated with any of these:

CuO + C → Cu + CO

CuO + CO → Cu + CO2

CuO + H2 → Cu + H2O

It is usually made in the laboratory by heating copper(II) carbonate, nitrate, or hydroxide:

2Cu(NO3)2 → 2CuO + 4NO2 + O2

Copper(II) oxide is a typical basic oxide, dissolving readily in most dilute acids.