Ethane-1,2-diylbis(methyl­phosphinic acid)

In the title compound, C(4)H(12)O(4)P(2), there are two crystallographically independent half-mol­ecules in the asymmetric unit, both molecules lying on centres of symmetry. Each mol­ecule is connected on both sides to neighbouring mol­ecules via strong O—H⋯O hydrogen bonds. The –POOH groups accept and donate one hydrogen bond in interactions with the neighbouring –POOH group of the adjacent mol­ecule, to give one-dimensional chains along [10[Image: see text]]. As each phosphinic acid group donates and accepts one hydrogen bond, the connection between the mol­ecules is best described by a ring motif which can be classified by the Etter symbol R (2) (2)(8).