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⁺·­C₂H₆O₆P₂^2?·2H₂O, 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.