Piperazinediium bis[bis(pyridine-2,6-dicarboxylato)ferrate(III)] monohydrate

The asymmetric unit of the title compound, (C4H12N2)[ Fe(C7H3NO4)(2)](2)center dot H2O or (pipzH(2))(2+)center dot 2[Fe(pydc)(2)](-)center dot H2O (pipz is piperazine and pydcH(2) is pyridine-2,6-dicarboxylic acid), contains one dication, two anions and one uncoordinated water molecule. In the anions, each Fe-III ion is hexa-coordinated by four O [Fe-O = 2.005 (2)-2.044 (2) angstrom] and two N [Fe-N = 2.050 (2)-2.075 (2)angstrom] atoms in a distortedoctahedral geometry. An extensive three-dimensional network formed by classical O-H center dot center dot center dot O and N-H center dot center dot center dot O and weak C-H center dot center dot center dot O intermolecular hydrogen bonds stabilizes the crystal packing, which also exhibits pi-pi [centroid-centroid distances 3.500 (2)-3.533 (2)angstrom] and C-H center dot center dot center dot pi interactions.