Poly[[diaquabis(μ-oxalato-κ4O1,O2:O1′,O2′)bis(μ3-5-oxidopyridin-1-ium-3-carboxylato-κ3O3:O3′:O5)diholmium(III)] dihydrate

Abstract

In the title compound, {[Ho2(C6H4NO3)2(C2O4)2(H2O)2]·2H2O}n, the HoIII atom is coordinated by three O atoms from three 5-hy­droxy­nicotinate ligands, four O atoms from two oxalate ligands, each lying on an inversion center, and one water mol­ecule in a distorted square-anti­prismatic geometry. The 5-hy­droxy­nicotinate ligand is protonated at the N atom and deprotonated at the hy­droxy group. The HoIII atoms are bridged by the carboxyl­ate and phenolate O atoms, forming a three-dimensional framework. N—H⋯O and O—H⋯O hydrogen bonds, as well as π–π inter­actions between the pyridine rings [centroid–centroid distance = 3.794 (2) Å], are observed.