Barium Oxalates Combined with Oxo-Anions and Organic Cations: Syntheses and Structures of Ba2(C2O4)(H2PO3)2 and C2H10N2·Ba(H2O)2(HC2O4)4

The syntheses and single-crystal structures of Ba2(C2O4)(H2PO3)2 (1) and C2H10N2·Ba(H2O)2(HC2O4)4 (2) are described. Compound 1 is a three-dimensional mixed-anion framework containing BaO9 coordination polyhedra, which approximate to monocapped square anti-prisms: the connectivity of the BaO9 units via edges and triangular faces leads to a sheet structure. The oxalate ion in 1 is substantially twisted about its C–C bond [dihedral angle between the CO2 groups = 33.8 (3)°]. Compound 2 is a molecular salt containing ethylenediammonium dications and [Ba(HC2O4)4(H2O)2]2– dianions, which are linked by O–HLO and N–HLO hydrogen bonds. The BaO10 coordination polyhedron can be described as a distorted pentagonal anti-prism. Crystal data: 1 (C2H4Ba2O10P2), Mr = 524.68, monoclinic, C2/c (No. 15), Z = 4, a = 12.3829 (3) A, b = 7.9124 (2) A, c = 11.0858 (3) A, b = 114.788 (2)°, V = 986.10 (4) A3, R(F) = 0.016, wR(F2) = 0.040. 2 (C10H18BaN2O10), Mr = 591.60, monoclinic, C2/m (No. 12), Z = 2, a = 12.7393 (7) A, b = 13.0111 (7) A, c = 5.6050 (3) A, b = 104.208 (4)°, V = 900.62 (8) A3, R(F) = 0.027, wR(F2) = 0.054.