catena-Poly[[[diaqua­diformatonickel(II)]-μ-1,4-bis­(1H-benzimidazol-1-yl)benzene] dihydrate]

In the title one-dimensional coordination polymer, {[Ni(CHO₂)₂(C₂₀H₁₄N₄)(H₂O)₂]·2H₂O}_n, the Ni^II atom lies on a crystallographic inversion centre. It is coordinated by two formate O atoms, two water O atoms and two N atoms from two 1,4-bis­(1H-benzimidazol-1-yl)benzene (bzb) ligands, resulting in a distorted trans-NiN₂O₄ octa­hedral coordination geometry. The bzb mol­ecule acts as a bridging ligand to connect the metal atoms into a chain propagating in [1]. The dihedral angle between the benzimidazole ring and the central benzene ring in the ligand is 38.16 (9)°. In the crystal, O—H...O hydrogen bonds crosslink the chains into (010) sheets.

catena-Poly[[tetra­kis­(1H-pyrazole-κN²)copper(II)]-μ-hexa­fluoridosilicato-κ²F:F′]

In the title one-dimensional coordination polymer, [Cu(SiF₆)(C₃H₄N₂)₄]_n, the Cu^II atom is coordinated by two hexafluoridosilicate F atoms and four pyrazole N atoms in a distorted trans-CuF₂N₄ octa­hedral environment. The dihedral angle between the planes of the pyrazlole rings in the asymmetric unit is 74.4 (3)°. The hexa­fluoridosilicate dianion acts as a bridging ligand, connecting the Cu^II atoms into a [1-10] chain. The Cu and Si atoms lie on special positions with 2/m site symmetry. In the crystal, intra­chain N—H...F hydrogen bonds occur and weak C—H...F inter­actions link the chains.