Poly[ethylenediammonium hydroxydeca-μ2-oxo-pentaborate]

The title compound, {C2H10N2 2+·B5O8(OH)2−} n , has been hydrothermally synthesized. The structure consists of two-dimensional polymeric sheets constructed from [B5O8(OH)]2− pentaborate anions. Adjacent borate sheets are linked by O—H...O hydrogen bonds into a three-dimensional framework with channels running along one direction. The ethylenediammonium cations lie on centres of inversion within the channels, interacting with the framework through N—H...O hydrogen bonds.