Materials Data on Na2CrO4 by Materials Project

Abstract

Na2CrO4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.33 Å) and two longer (2.51 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent CrO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are two shorter (2.39 Å) and four longer (2.46 Å) Na–O bond lengths. Cr6+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 44–51°. There is two shorter (1.66 Å) and two longer (1.68 Å) Cr–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and one Cr6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one Cr6+ atom.