The molecular formula of basic copper carbonate is

Chemically speaking, basic copper carbonate is more correctly known as copper(II) carbonate hydroxide. It is an ionic compound made up of the ions hydroxide OH, carbonate CO2, and copper(II)$\left({\mathrm{Cu}}^{2+}\right)$. The formula for the chemical with this name is ${\mathrm{Cu}}_2{\mathrm{CO}}_3(\mathrm{OH}{)}_2$.