Pyridinium diaqua­bis­(methyl­enediphospho­nato-κ2 O,O′)chromate(III) tetra­hydrate

In the title complex, (C5H6N)[Cr(CH4O6P2)2(H2O)2]·4H2O, the CrIII atom, lying on an inversion centre, is coordinated by two bidentate methyl­ene diphospho­nate ligands and two water molecules in a distorted octa­hedral coordination geometry. The pyridinium cation is located on an inversion centre, with an N atom and a C atom sharing a position each at a half occupancy. A three-dimensional network is constructed by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds between the pyridin­ium cation, complex anion and uncoordinated water mol­ecules

Dicaesium diaqua­bis­(methyl­ene­diphospho­nato-κ2 O,O′)cobaltate(II)

The asymmetric unit of the title compound, Cs2[Co(CH4O6P2)2(H2O)2], is comprised of one bidentate methyl­enediphospho­nate ligand and one water mol­ecule which are coordinated to the CoII atom, as well as a caesium counter-cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octa­hedrally coordinated by six O atoms with Cs—O distances ranging from 3.119 (2) to 3.296 (2) Å. A three-dimensional network is formed through O—H⋯O hydrogen bonds

Disodium diaqua­bis­(methyl­enedi­phos­pho­nato-κ2 O,O′)cobaltate(II) dihydrate

In the title compound, Na2[Co(CH4O6P2)2(H2O)2]·2H2O, the asymmetric unit is composed of one methyl­enediphospho­nate ligand and one water mol­ecule, which both are coordinated to a CoII atom, as well as a non-coordinated water mol­ecule and a sodium cation. The CoII atom occupies a special position on a crystallographic inversion centre. The slightly distorted CoIIO6 octa­hedral coordination environment is composed of two bidentate methyl­enediphospho­nate ligands and two coordinated water mol­ecules in trans positions. The sodium ion is octa­hedrally coordinated to six O atoms with Na—O distances ranging from 2.3149 (12) to 2.6243 (12) Å. An extensive three-dimensional network of inter­molecular as well as intra­molecular O—H⋯O and C—H⋯O hydrogen bonding inter­acions is present