Crystal structure of 4-(di-methyl-amino)-pyridinium cis-di-aqua-bis-(oxalato-κ(2) O,O')ferrate(III) hemihydrate.

The Fe(III) ions in the hybrid title salt, (C7H11N2)[Fe(C2O4)2(H2O)2]·0.5H2O, show a distorted octa-hedral coordination environment, with four O atoms from two chelating oxalate dianions and two O atoms from two cis aqua ligands. The average Fe-O(oxalate) bond length [2.

2-Amino-pyridinium trans-diaqua-bis-(oxalato-κ(2)O,O)chromate(III).

In the title hybrid salt, (C(5)H(7)N(2))[Cr(H(2)O)(2)(C(2)O(4))(2)], the Cr(III) ion is coordinated in a slightly distorted octa-hedral environment by four O atoms from two oxalate ligands in the equatorial plane and by two water O atoms in the axial sites. The 2-amino-pyridinium cation is disordered over two sets of sites in a 0.800 (7):0.

catena-Poly[[[(oxamide dioxime-κ2N,N')copper(II)]-μ-L-tartrato-κ4O1,O2:O3,O4] tetrahydrate]: a chiral nanochannel framework hosting solvent water molecules.

The crystal structure of the title compound, {[Cu(C(4)H(4)O(6))(C(2)H(6)N(4)O(2))]·4H(2)O}(n), contains the central Cu(II) cation in a distorted octahedral coordination, symmetrically chelated by the two imine N atoms of a neutral oxamide dioxime (H(2)oxado) ligand [Cu-N = 1.9829 (16) Å] and unsymmetrically bis-chelated by two halves of the L-(+)-tartrate(2-) (tart) ligands, each half being linked to the Cu(II) cation via the deprotonated carboxylate group and protonated hydroxy group [Cu-O = 1.9356 (14) and 2.

4-(Dimethyl-amino)-pyridinium trans-diaqua-bis-[oxalato(2-)-κO,O]chromate(III).

In the title salt, (C(7)H(11)N(2))[Cr(C(2)O(4))(2)(H(2)O)(2)], the asymmetric unit contains one half-cation and one half-anion. The Cr atom, the C and N atoms involved in C- N(exocyclic) bonding and the N and H atoms of N-H groups lie on twofold rotation axis. The Cr(III) atom of the complex anion is six-coordinated in a distorted (4 + 2) octa-hedral geometry with four equatorial O atoms of two nearly coplanar oxalate and two quasi-axial aqua O atoms.

{[Na1(μ-H(2)O)Na2](2)[(C(2)O(4))(2)Cr(μ-OH)(2)Cr(C(2)O(4))(2)]·H(2)O}(n), a novel hydrated form.

The unit cell of the title compound, poly[[μ-aqua-μ-hydroxido-di-μ-oxalato-chromium(III)disodium] monohydrate], {[CrNa(2)(C(2)O(4))(2)(OH)(H(2)O)]·H(2)O}(n), contains four [Na1(μ-H(2)O)Na2][(C(2)O(4))(2)Cr(μ-OH)·H(2)O] formula units, each of which consists of two crystallographically independent Na(+) sites (bridged by one aqua ligand), one half of a centrosymmetric di-μ-hydroxido-bis-[cis-bis-(oxalato)chromate(III)] dimer, [(C(2)O(4))(2)Cr(μ-OH)(2)Cr(C(2)O(4))(2)](4-), and one uncoordin-ated water mol-ecule. The structure is best described as a coordination polymer in which the three-dimensional lattice framework is realized by the inter-connection of the metallic atoms via the O atoms of the aqua, hydroxide and oxalate ligands. One Na atom is hepta-coordinated by one water, one hydroxide and five oxalate O atoms, whilst the other is penta-coordinated by one water and four oxalate O atoms.

Tris(oxamide dioxime-κN,N')nickel(II) sulfate penta-hydrate.

The asymmetric unit of the title compound, [Ni(C(2)H(6)N(4)O(2))(3)]SO(4)·5H(2)O, contains two complex cations, two sulfate anions and ten lattice water mol-ecules. In both independent cations, the central Ni(II) ion adopts a distorted octa-hedral coordination involving six imino N atoms of three bidentate oxamide dioxime ligands. The bulk structure is achieved by a three-dimensional network of O-H⋯O and N-H⋯O hydrogen bonds which inter-link the ionic partners and some water mol-ecules in such a manner that the lattice framework thus formed defines channels parallel to [100].

Monoclinic polymorph of poly[[di-μ-aqua-triaquadi-μ-oxalato-barium(II)-copper(II)] monohydrate].

A monoclinic polymorph of the title compound, {[BaCu(C(2)O(4))(2)(H(2)O)(5)]·H(2)O}(n), is reported. The structure is best described as a coordination polymer where the Cu(II) and Ba(II) centers are coordinated by five and nine O atoms, respectively, in capped quadratic antiprismatic and tetragonal pyramidal geometries. The polymerization arises due to the presence of bridging mono- and bidentate oxalate ligands as well as bridging water mol-ecules.