Reinvestigation of layered poly[aquasodium(I) [[aquasamarium(III)]-di-μ-aqua-μ3-pyridine-2,6-dicarboxylato-μ2-pyridine-2,6-dicarboxylato] trihydrate

Abstract

The crystal structure of the title compound, {[NaSm(C7H3NO4)2(H2O)4]·3H2O}n, was first reported by van Albada, Gorter & Reedijk [(1999), Polyhedron, 18, 1821–1824]. It has now been reinvestigated and confirmed from single-crystal data, giving greater understanding of the role of the water mol­ecules. The two-dimensional layers found in the compound are built up from six-coordinate NaO6 polyhedra and nine-coordinate SmN2O7 polyhedra. The former share edges with each other along the c axis and the latter are bridged by carboxyl­ate groups of pyridine-2,6-dicarboxylate anions along the b axis. Eight-membered rings of water mol­ecules, connected to one another by hydrogen bonding, are formed in the inter­layer spaces.