Materials Data on Na2Cr(HO)8 by Materials Project

Abstract

Na2Cr(HO)8 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent CrO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.36–2.48 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.94 Å. Cr6+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with two equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Cr–O bond distances ranging from 1.65–1.70 Å. There are eight inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one Cr6+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and two H1+ atoms. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and one Cr6+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one Cr6+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom.