Calcite group structures are taken by nitrates and carbonates of relatively small cations, including Li, Na, Mg, Ca, Fe 2+, Zn, Co 2+, and Cd. The structure of calcite and its related species is ionic and resembles that of NaCl, the place of the spherical Cl ions being taken by planar (CO 3) 2-or (NO 3) 1-groups. These groups are arranged in parallel position in the crystal with their ...
