Bis(ethyl-enedi-ammonium) μ-ethyl-enedi-aminetetra-acetato-1κ 3 O , N , O ':2κ 3 O '', N ', O '''-bis-[tri-oxidomolybdate(VI)] tetra-hydrate.

The title compound, (C 2 H 10 N 2 ) 2 [(C 10 H 12 N 2 O 8 )(MoO 3 ) 2 ]·4H 2 O, which crystallizes in the monoclinic C 2/ c space group, was obtained by mixing molybdenum oxide, ethyl-enedi-amine and ethyl-enedi-amine-tetra-acetic acid (H 4 edta) in a 2:4:1 ratio. The complex anion contains two MoO 3 units bridged by an edta 4- anion. The midpoint of the central C-C bond of the edta 4- anion is located on a crystallographic inversion centre. The independent Mo atom is tridentately coordin-ated by a nitro-gen atom and two carboxyl-ate groups of the edta 4- ligand, together with the three oxo ligands, producing a distorted octa-hedral coordination environment. In the three-dimensional supra-molecular crystal structure, the dinuclear anions, the organo-ammonium counter-ions and the solvent water mol-ecules are linked by N-H⋯O w , N-H⋯O edta and O-H⋯O hydrogen bonds.