Penta-aqua-tri-μ(3)-hydroxido-tris-(imino-diacetato)-μ(3)-oxido-tetra-hedro-calcium(II)tricobalt(III) 2.54-hydrate.

In the title compound, [CaCo(3)(C(4)H(5)NO(4))(3)(OH)(3)O(H(2)O)(5)]·2.54H(2)O, the Co atom is octa-hedrally coordinated by one imino-diacetate (ida) dianion as a facial O,N,O'-tridentate ligand, two μ(3)-OH groups and one μ(3)-O ligand, forming an partial Co(3)O(4) cubane cluster. This unit coordinates to a Ca(II) cation in an O,O',O''-tridentate fashion, generating a distorted CaCo(3)O(4) cubane-type cluster. The Ca-μ(3)-O distances [2.429†(5)-2.572†(6)†à ] are much longer than the Co-μ(3)-O bonds [1.895†(5)-1.941†(5)†à ]. The Ca(II) cation is also coord-inated by five water mol-ecules with Ca-O distances in the range 2.355†(6)-2.543†(6)†à . There are three additional uncoordinated water mol-ecules in the asymmetric unit, the occupancy of which refined to 0.54†(3). In H(2)O (or D(2)O), the title complex hydrolyses to Ca(2+) (aq) cations and [Co(3)(ida)(3)(μ(2)-OH)(3)(μ(3)-O)](2-) anions.