Tetra-aqua-bis-(tetra-zolido-κN)magnesium.

In the crystal structure of the title compound, [Mg(CHN(4))(2)(H(2)O)(4)], the Mg(II) atom is six-coordinated by two N atoms from two tetra-zolide anions and four O atoms from four coordinated water mol-ecules in a slightly distorted octa-hedral geometry. The Mg atom is located on centres of inversion whereas the tetra-zolide anion and the water mol-ecules occupy general positions. The crystal packing is stabilized by intermolecular O-H⋯N hydrogen bonding between the tetra-zolide anions and the coordinated water mol-ecules.

Bis(µ-5-carboxyl-atotetra-zolido)bis-[aqua-(2,2'-bipyrid-yl)cadmium(II)].

In the title dinuclear Cd(II) complex, [Cd(2)(C(2)N(4)O(2))(2)(C(10)H(8)N(2))(2)(H(2)O)(2)], each Cd atom is in a slightly distorted octa-hedral coordination by two N atoms and one O atom of two 1H-tetra-zole-5-carboxyl-ate (TZC) ligands, two N atoms of a 2,2'-bipyridyl ligand and one water O atom. The TZC ligand acts in a tridentate N,O-chelating N-bridging mode to two symmetry-equivalent Cd(II) atoms. The complex reveals mol-ecular C(i) symmetry. Extensive O-H⋯O hydrogen bonding plays an important role in the crystal packing.

Diaqua-bis-(3-nitro-benzoato-κO)bis-[1H-5-(3-pyrid-yl)-3-(4-pyrid-yl)-1H-1,2,4-triazole-κN]cobalt(II) dihydrate.

In the centrosymmetric title compound, [Co(C(7)H(4)NO(4))(2)(C(12)H(9)N(5))(2)(H(2)O)(2)]·2H(2)O, the Co(II) atom, located on an inversion center, is coordinated by two N atoms [Co-N = 2.155 (3) Å] and four O atoms [Co-O = 2.099 (2)-2.117 (3) Å] in a distorted octa-hedral geometry. Inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds link the components into a three-dimensional supramolecular framework.

Tetra-aqua-bis[3-(3-pyrid-yl)-5-(4-pyrid-yl)-1,2,4-triazolido]nickel(II) dihydrate.

In the title compound, [Ni(C(12)H(8)N(5))(2)(H(2)O)(4)]·2H(2)O, the Ni(II) atom is coordinated by the two N atoms [Ni-N = 2.094 (3) Å] and four O atoms [Ni-O = 2.063 (3)-2.083 (2) Å] in a distorted octa-hedral geometry. The mol-ecule is centrosymmetric and the Ni(II) atom is located on an inversion center. Inter-molecular O-H⋯N and O-H⋯O hydrogen bonds link the complex into a three-dimensional supra-molecular framework.

Tetra-aqua-bis(3,5-di-4-pyridyl-1H-1,2,4-triazolido)cadmium(II) dihydrate.

In the title compound, [Cd(C(12)H(8)N(5))(2)(H(2)O)(4)]·2H(2)O, the Cd(II) atom is located on an inversion center and is coordinated by the two N atoms [Cd-N = 2.278 (2) Å] and four O atoms [Cd-O = 2.304 (2)-2.322 (2) Å] in a distorted octa-hedral geometry. Inter-molecular O-H⋯O and O-H⋯N hydrogen bonds link the complex into a three-dimensional supra-molecular framework.