Materials Data on Na3CrO4 by Materials Project

Abstract

Na3CrO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four equivalent CrO4 tetrahedra, corners with six NaO4 tetrahedra, and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.27–2.36 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four equivalent NaO4 tetrahedra, corners with four equivalent CrO4 tetrahedra, and edges with two equivalent NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.26–2.43 Å. Cr5+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with twelve NaO4 tetrahedra. There is two shorter (1.73 Å) and two longer (1.74 Å) Cr–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted tetrahedral geometry to three Na1+ and one Cr5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Cr5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Cr5+ atom.