1-Dimensional and 2-dimensional coordination network structures in the Ba-Ce-dipicH2 system (dipicH2Â =Â dipicolinic acid)

Coordination polymers with similar stoichiometries, but very different network structures form in the Ce-Ba-dipicH2 system depending on the crystallization conditions. Ba(OH2)6Ce(dipic)3 (A) is a structural analog of SrCl2 · 6H2O. At the vertices of the triangles are Ce(dipic)32- ions, while a Ba(H2O)92+ chain is threaded through the triangles. Its polymorph (B) has a structure analogous to that of PbO. The dark junctions in the net are Ce(dipic)32- ions while the lighter junctions represent carboxylate linked Ba(H2O)42+ ions.