A structural hierarchy in the hydrogen-bonded adduct ethane-1,2-diphosphonic acid-4,4 '-bipyridyl-water (1/1/2): an N-component N-dimensional structure (N=3) with substructures having N=1 and 2

The title compound, 4,4'-bipyridinium ethane-1,2-diyl-1,2-diphosphonate dihydrate, is a hydrated salt, C10H10N22+.-C-2 H6O6P22-. 2H(2)O, in which the components are linked by extensive hydrogen bonding. The cations and anions lie on inversion centres and with the water molecules each form separate one-component one-dimensional chains along [100]: the anions and the water molecules form a two-component two-dimensional substructure, (001) sheets, while the cations and anions form a second two-component two-dimensional substructure, (011) sheets. All three components combine to form a three-dimensional framework.