Materials Data on NaAlCr2O10 by Materials Project
NaCr2AlO10 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na is bonded to eight O atoms to form distorted NaO8 hexagonal bipyramids that share corners with four equivalent CrO4 tetrahedra, edges with two equivalent AlO6 octahedra, and edges with two equivalent CrO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.53–2.81 Å. Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with two equivalent NaO8 hexagonal bipyramids, corners with two equivalent AlO6 octahedra, and an edgeedge with one NaO8 hexagonal bipyramid. The corner-sharing octahedra tilt angles range from 33–44°. There are a spread of Cr–O bond distances ranging from 1.62–1.73 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with four equivalent CrO4 tetrahedra and edges with two equivalent NaO8 hexagonal bipyramids. There are a spread of Al–O bond distances ranging from 1.87–1.91 Å. There are five inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Al atom. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one Na, one Cr, and one Al atom. In the third O site, O is bonded in a 3-coordinate geometry to one Na, one Cr, and one Al atom. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and one Cr atom. In the fifth O site, O is bonded in a single-bond geometry to one Na and one Cr atom.