Materials Data on NaCo2HSe2O7 by Materials Project
NaCo2(SeO3)2(OH) crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with five CoO6 octahedra. The corner-sharing octahedra tilt angles range from 63–77°. There are three shorter (2.31 Å) and one longer (2.36 Å) Na–O bond lengths. There are two inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent NaO4 tetrahedra and edges with four CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.08–2.14 Å. In the second Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent NaO4 tetrahedra and edges with two equivalent CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.08–2.18 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are two inequivalent Se2+ sites. In the first Se2+ site, Se2+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.73 Å) and one longer (1.77 Å) Se–O bond length. In the second Se2+ site, Se2+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.73 Å) and two longer (1.75 Å) Se–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one Co4+, and one Se2+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co4+ and one Se2+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three Co4+ and one H1+ atom. In the fourth O2- site, O2- is bonded to one Na1+, two equivalent Co4+, and one Se2+ atom to form distorted corner-sharing ONaCo2Se tetrahedra. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Co4+, and one Se2+ atom.