Cobalt, zinc, and manganese complexes of cyclopropane-1,1-dicarboxylic acid have been prepared in an aqueous solution from the corresponding metal carbonates. These complexes have 6 mol of water per formula unit and thermally decompose via loss of water, which is followed by a two-stage decomposition of the hydrogencyclopropane-1,1-dicarboxylate ligand with a metal oxide residue. The metal centre is expected to have octahedral symmetry in accordance with single crystal X-ray diffraction data obtained for the cobalt compound.