Materials Data on NaH2SeO4 by Materials Project
NaH2SeO4 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Na is bonded to six O atoms to form NaO6 octahedra that share corners with three equivalent SeO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.40–2.51 Å. There are three inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.65 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.97 Å. There are two inequivalent Se sites. In the first Se site, Se is bonded in a trigonal non-coplanar geometry to three O atoms. There is one shorter (1.67 Å) and two longer (1.81 Å) Se–O bond length. In the second Se site, Se is bonded to four O atoms to form SeO4 tetrahedra that share corners with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Se–O bond distances ranging from 1.66–1.69 Å. There are six inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to two equivalent Na and one Se atom. In the second O site, O is bonded in a distorted T-shaped geometry to two equivalent Na and one Se atom. In the third O site, O is bonded in a 3-coordinate geometry to one Na, one H, and one Se atom. In the fourth O site, O is bonded in a distorted single-bond geometry to one Na, one H, and one Se atom. In the fifth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Na and one Se atom. In the sixth O site, O is bonded in a distorted water-like geometry to two equivalent Na and two H atoms.