A polymorph structure of copper(II) hydrogenphosphite dihydrate

Abstract

The title compound, poly[[diaquacopper(II)]-μ3-hydrogenphosphito], [Cu(HPO3)(H2O)2]n, (I), has been prepared by hydrothermal synthesis at 393 K. Its non-centrosymmetric polymorph structure, (II), was known previously and has been redetermined at 193 (2) K [El Bali & Massa (2002). Acta Cryst. E58, i29–i31]. The Cu atoms in (I) and (II) are square-pyramidal coordinated. A distorted octahedral geometry around the Cu atoms is considered by including the strongly elongated apical distances of 2.8716 (15) Å in (I) and 3.000 (1) Å in (II). The Cu...Cu separation of the dimeric unit is 3.1074 (3) Å. The secondary building units (SBU) (the Cu2O2 dimer and two HPO3 units) in (I) are inversion related and form a two-dimensional layered structure, with sheets parallel to the bc plane, whereas in the structure of (II), the chain elements are connected via screw-axis symmetry to form a three-dimensional microporous framework. In both polymorph structures, strong O—H...O hydrogen bonds are observed.