Abstract: | The asymmetric unit of the title compound, {Cu(C4O4)(C6H6N2O)2(H2O)2]·2H2O}n, consists of one pyridine‐4‐carboxamide (isonicotinamide or ina) ligand, one‐half of a squarate dianion, a coordinated aqua ligand and a solvent water molecule. Both the CuII and the squarate ions are located on inversion centers. The CuII ions are octahedrally surrounded by four O atoms of two water molecules and two squarate anions, and by two N atoms of the isonicotinamide ligands. The crystal structure contains chains of squarate‐1,3‐bridged CuII ions. These chains are held together by N—H?O and O—H?O intermolecular hydrogen‐bond interactions, forming an extensive three‐dimensional network. |