Lithium hydrogenselenite, LiHSeO3: Structure refinement using multiple-wavelength synchrotron radiation data

Abstract

Abstract The crystal structure of LiHSeO3 has been redetermined using synchrotron radiation X-ray diffraction data collected up to sin θ/λ = 0.575 Å−1 at five different wavelengths, four close to the Se K-absorption edge (0.97974 Å), the fifth at 0.560 Å. Each data set was initially refined separately (460–470 unique reflections, 53 parameters), but a joint refinement of all data (2319 reflections, 61 parameters) resulted in substantially decreased standard deviations of atomic parameters and derived quantities. LiHSeO3 crystallizes in the orthorhombic and non-centrosymmetric space group P212121 [Z = 4, a = 5.0551(2) Å, b = 11.1874(6) Å, c = 5.2202(3) Å, V = 295.22(8) Å3]. Its crystal structure consists of pyramidal HSeO3 − ions with two shorter Se–O [both 1.660(1) Å] and one longer Se–OH [1.782(1) Å]. The HSeO3 − are linked into spiral chains along [100] by hydrogen bonds [O(3)…O(1) = 2.622(1) Å, O(3)–H = 0.77(2) Å, O(1)…H = 1.87(2) Å]. Each of the Li+ is tetrahedrally surrounded by oxygens at distances 1.910(2) Å, 1.943(2) Å, 1.968(3) Å, and 2.021 (3) Å, joining the HSeO3 − chains into a space-filling three-dimensional network.