The title complex [CaCo(C3H2O4)2(H2O)4]n with a formula of C6H12CaCoO12 and Mr = 375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 14.195(9), b = 7.708(5), c = 13.441(8) ·, β = 119.575(9)°, V = 1279.0(14) ·3, Dc = 1.948 g/cm3, μ = 1.803 mm·1, F(000) = 764 and Z = 4. The final R = 0.0245 and wR = 0.0652 for 1344 observed reflections with I > 2σ(I). The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate ligands. The Ca(II) cation on a twofold axis is coordinated by two water molecules and six malonate O atoms. The Co(II) cation which lies in a centre of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane, with the shortest Co·Co distance of 6.961(5) A. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds. The title complex [CaCo (C3H2O4) 2 (H2O) 4] n with a formula of C6H12CaCoO12 and Mr = 375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2 / c with a = B = 7.708 (5), c = 13.441 (8) ·, β = 119.575 (9) °, V = 1279.0 (14) · 3, Dc = 1.948 g / cm3, μ = 1.803 mm · 1 , F (000) = 764 and Z = 4. The final R = 0.0245 and wR = 0.0652 for 1344 observed reflections with I> 2σ (I). The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate The Ca (II) cation on a twofold axis is coordinated by two water molecules and six malonate O atoms. The Co (II) cation which lies in a center of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane, with the shortest Co · Co distance of 6.961 (5) A. The whole 3D structure is maintained and stabilized by the presence of hydro gen bonds.