Abstract

In the title compound, {Cu2(C4H2O4)2(H2O)2.3H2O}n, CuII ions with square-pyramidal coordination are bridged by exotridentate maleate dianions into Cu2(maleate)2(H2O)2n layers coincident with the bc crystal plane. The interlamellar regions contain hydrogen-bonded cyclic water hexamers which facilitate layer stacking into a pseudo-three-dimensional crystal structure. The water hexamers themselves are formed by the operation of crystallographic inversion centers on sets of three crystallographically distinct water molecules of hydration.