Binary salt of a palladium(II) complex with (phosphonomethyl)phosphonic (medronic) acid comprising 'handbell-like' [Pd{μ-CH2(PO3)2}]3 units.

The asymmetric unit of the title compound, dipotassium bis[hexaaquanickel(II)] tris(μ(2)-methylenediphosphonato)tripalladium(II) hexahydrate, K(2)[Ni(H(2)O)(6)](2)[Pd(3){CH(2)(PO(3))(2)}(3)]·6H(2)O, consists of half a {[Pd{CH(2)(PO(3))(2)}](3)}(6-) anion [one Pd atom (4e) and a methylene C atom (4e) occupy positions on a twofold axis] in a rare 'handbell-like' arrangement, with K(+) and [Ni(H(2)O)(6)](2+) cations to form the neutral complex, completed by three solvent water molecules. The {[Pd{CH(2)(PO(3))(2)}](3)}(6-) units exhibit close Pd···Pd separations of 3.0469 (4) Å and are packed via intermolecular C-H···Pd hydrogen bonds.

Poly[[diaqua[μ(5)-(R,S)-2-({2-[(1,2-di-carboxyl-atoeth-yl)amino]-eth-yl}amino)-butane-dioato]cobaltate(III)sodium] di-hydrate].

In the asymmetric unit of the title coordination polymer, {[CoNa(C(10)H(12)N(2)O(8))(H(2)O)(2)]·2H(2)O}(n), the Co(II) ion is coord-inated in a distorted octa-hedral environment, defined by two N atoms and four carboxyl-ate O atoms. Two Co(II) ions and two 2-({2-[(1,2-dicarboxyl-atoeth-yl)amino]-eth-yl}amino)-butane-dio-ate (EDDS) ligands form a dimeric complex dianion [Co(2)(EDDS)(2)]. These dimeric units are connected via Na(+) ions, forming a three-dimensional polymeric structure.

Diaqua-bis-(dihydrogen 3-aza-niumyl-1-hy-droxy-propyl-idene-1,1-di-phos-phon-ato-κO,O')cobalt(II).

The asymmetric unit of title compound, [Co(C(3)H(10)NO(7)P(2))(2)(H(2)O)(2)], contains one half-mol-ecule of the complex. The Co(II) atom is located on an inversion centre and displays a distorted octa-hedral coordination geometry defined by four O atoms of two 3-aza-niumyl-1-hy-droxy-propyl-idene-1,1-bis-phospho-nato ligands in the equatorial plane and two water mol-ecules located in axial positions. The ligand mol-ecules, which exist in a zwitterionic state, form two six-membered chelate rings with chair conformations.

A second triclinic polymorph of (1-ammonio-1-phosphono-eth-yl)phospho-nate.

The asymmetric unit of the second polymorph of the title compound, C(2)H(9)NO(6)P(2), contains one mol-ecule existing as a zwitterion. The N atom of the ammonio group is protonated and one of the phospho-nic acid groups is deprotonated. Bond lengths and angles are similar in both polymorphs.

trans-Bis[(1-ammonio-pentane-1,1-di-yl)diphospho-nato-κO,O']diaqua-copper(II).

In the title compound, [Cu(C(5)H(14)NO(6)P(2))(2)(H(2)O)(2)], the Cu(II) atom occupies a special position on an inversion centre. It exhibits a distorted octa-hedral coordination environment consisting of two O,O'-bidentate (1-ammonio-pentane-1,1-di-yl)diphospho-nate anions in the equatorial plane and two trans water mol-ecules located in axial positions. The ligand mol-ecules are coordinated to the Cu(II) atom in their zwitterionic form via two O atoms from different phospho-nate groups, creating two six-membered chelate rings with a screw-boat conformation.

Bis[(1-ammonio-ethane-1,1-di-yl)diphospho-nato-κO,O']diaqua-nickel(II) nona-hydrate.

The title compound, [Ni(C(2)H(8)NO(6)P(2))(2)(H(2)O)(2)]·9H(2)O, exhibits a slightly distorted octa-hedral coordination environment around the Ni(II) atom. It contains two mol-ecules of 1-amino--ethyl-idenediphospho-nic acid in the zwitterionic form, coord-inated via O atoms from two phospho-nate groups and creating two six-membered chelate rings. Two water mol-ecules in cis positions complete the coordination environment of the Ni(II) atom.

Bis(1-ammonio-ethane-1,1-diyl-diphos-phonato-κO,O')diaqua-cobalt(II) nona-hydrate.

In the title compound, [Co(C(2)H(8)NO(6)P(2))(2)(H(2)O)(2)]·9H(2)O, the Co(II) atom has a slightly distorted octa-hedral coordination environment consisting of four deprotonated phospho-nate O atoms of two independent 1-amino-ethyl-idendiphospho-nate anions and complemented by the O atoms of two water mol-ecules in cis positions. The anions exists in the zwitterionic form (protonated amino group and two deprotonated phospho-nate O atoms) and constitute two six-membered chelate rings. The crystal structure also contains nine partly disordered uncoordinated water mol-ecules, which create an extensive three-dimensional network of strong O-H⋯O and N-H⋯O hydrogen bonds.