Redetermination of hexa-sodium hepta-molybdate(VI) 14-hydrate.

The structure of the title compound, Na(6)(Mo(7)O(24))·14H(2)O, has been redetermined [Sjöbom & Hedman (1973). Acta Chem. Scand.27, 3673-3674] and the hydrogen atoms have been located. The Na(+) cations adopt distorted octa-hedral geometries and the structure of the [Mo(7)O(24)](6-) anion is consistent with those of other hepta-molbydates. In the crystal, numerous O-H⋯O hydrogen bonds help to establish the packing.

Tetra-kis(2-methyl-benzimidazolium) ß-octa-molybdate(VI).

The asymmetric unit of the title compound, (C(8)H(9)N(2))(4)[Mo(8)O(26)], consists of two 2-methyl-benzimidazolium cations and one-half of a ß-Mo(8)O(26) (4-) anion, which is completed by crystallographic inversion symmetry. An extensive net of N-H⋯O hydrogen bonds between the cations and anions contribute to the crystal packing.

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]cadmium(II)} dodeca-molybdo(V,VI)phosphate hexa-hydrate.

The hydro-thermally prepared title compound, [Cd(C(8)H(7)N(3))(3)](2)[PMo(12)O(40)]·6H(2)O, is isotypic with its Mn(II) analogue [Hao et al. (2010 ▶). Acta Cryst. E66, m231-m232]. The Cd(II) cation is in a distorted octa-hedral environment, coordinated by six N atoms from three chelating 3-(2-pyrid-yl)-1H-pyrazole ligands. In the reduced heteropolyanion, two O atoms of the central PO(4) group ( symmetry) are equally disordered about an inversion centre. N-H⋯O and O-H⋯O hydrogen bonds contribute to the crystal packing. Compared with the Mn(II) analogue, the Cd-N bond lengths are longer at 2.316 (7)-2.334 (6) Å, versus 2.224 (6)-2.283 (5) Šfor Mn-N, whereas all other bond lengths and angles and the hydrogen-bonding motifs are very similar in the two structures.

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]iron(II)} dodeca-molybdo(V,VI)phosphate hexa-hydrate.

Crystals of the title compound, [Fe(C(8)H(7)N(3))(3)](2)[PMo(12)O(40)]·6H(2)O, prepared under hydro-thermal conditions, are isotypic with the Mn(2+) and Cd(2+) analogues. The Fe(2+) cation is in a distorted octa-hedral coordination by six N atoms from three chelating 3-(2-pyrid-yl)-1H-pyrazole ligands. The heteropoly-anion [PMo(12)O(40)](4-) is a one-electron reduced species in which two O atoms of the central PO(4) group ( symmetry) are equally disordered about an inversion centre. N-H⋯O and O-H⋯O hydrogen bonds make a contribution to the crystal packing. The Fe-N bond lengths [2.085 (19)-2.15 (2) Å] are somewhat shorter than the Mn-N and Cd-N bond lengths [2.224 (6)-2.283 (5) and 2.316 (7)-2.334 (6) Å, respectively]. All other bond lengths and angles and the hydrogen-bonding motifs are very similar in the isotypic structures.

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]nickel(II)} dodeca-molybdo(V,VI)phosphate hexa-hydrate.

The hydro-thermally prepared title compound, [Ni(C(8)H(7)N(3))(3)](2)[PMo(12)O(40)]·6H(2)O, is a member of the isotypic series [(M(C(8)H(7)N(3))(3)](2)[PMo(12)O(40)]·6H(2)O where M is Mn, Cd, and Fe. The Ni(2+) cation is in a distorted octa-hedral environment, coordinated by six N atoms from three chelating 3-(2-pyrid-yl)-1H-pyrazole ligands. In the one-electron reduced heteropolyanion, two O atoms of the central PO(4) group ( symmetry) are equally disordered about an inversion centre. N-H⋯O and O-H⋯O hydrogen bonds contribute to the crystal packing. Compared with the isotypic structures, the main difference is related with the M-N bond lengths, whereas all other bond lengths, angles and the hydrogen-bonding motifs are very similar.

(4-Amino-benzene-sulfonato)-hepta-aqua-gadolinium(III) 4-amino-benzene-sulfonate nitrate 4,4'-bipyridyl tetra-solvate dihydrate.

In the title compound, [Gd(C(6)H(6)O(3)S)(H(2)O)(7)](C(6)H(6)O(3)S)(NO(3))·4C(10)H(8)N(2)·2H(2)O, the Gd(III) ion is octa-coordinated by seven water mol-ecules and one O-bonded 4-amino-benzene-sulfonate anion in a square-anti-prismatic arrangement. In the crystal, the components are linked by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds.

3-Methyl-4H-chromen-4-one.

In the title chromenone derivative, C(10)H(8)O(2), the two fused six-membered rings are coplanar, with a mean deviation of 0.0261 (1) Šfrom the plane through the non-H atoms of the rings. The carbonyl and methyl substituents of the pyran ring also lie close to that plane, with the O and C atoms deviating by 0.0557 (1) and 0.1405 (1) Å, respectively. In the crystal, weak C-H⋯O contacts form chains along the a axis.