At ambient temperatures, it is an ionic solid (a salt) consisting of copper(II) cations Cu2+ and carbonate anions CO2−3.

This compound is rarely encountered because it is difficult to prepare[2] and readily reacts with water moisture from the air.

The bulk of the products was well-crystallized malachite Cu2CO3(OH)2, but a small yield of a rhombohedral substance was also obtained, claimed to be CuCO3.

[2] Reliable synthesis of true copper(II) carbonate was reported for the first time in 1973 by Hartmut Ehrhardt et al.

[3] The solubility product of the true copper(II) carbonate was measured by Reiterer and others as pKso = 11.45 ± 0.10 at 25 °C.