NaCr2Al3O14 crystallizes in the trigonal R-3m space group. Na(1) is bonded to six equivalent O(2) and six equivalent O(3) atoms to form NaO12 cuboctahedra that share corners with six equivalent Cr(1)O4 tetrahedra and faces with six equivalent Al(1)O6 octahedra. Cr(1) is bonded to one O(1) and three equivalent O(2) atoms to form CrO4 tetrahedra that share corners with three equivalent Na(1)O12 cuboctahedra and corners with three equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. Al(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Cr(1)O4 tetrahedra, and faces with two equivalent Na(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 35°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Cr(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one Al(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Na(1) and two equivalent Al(1) atoms.
NaCr2Al3O14 crystallizes in the trigonal R-3m space group. Na(1) is bonded to six equivalent O(2) and six equivalent O(3) atoms to form NaO12 cuboctahedra that share corners with six equivalent Cr(1)O4 tetrahedra and faces with six equivalent Al(1)O6 octahedra. All Na(1)-O(2) bond lengths are 2.70 Å. All Na(1)-O(3) bond lengths are 2.87 Å. Cr(1) is bonded to one O(1) and three equivalent O(2) atoms to form CrO4 tetrahedra that share corners with three equivalent Na(1)O12 cuboctahedra and corners with three equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. The Cr(1)-O(1) bond length is 1.60 Å. All Cr(1)-O(2) bond lengths are 1.70 Å. Al(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Cr(1)O4 tetrahedra, and faces with two equivalent Na(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 35°. Both Al(1)-O(2) bond lengths are 1.97 Å. All Al(1)-O(3) bond lengths are 1.85 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Cr(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one Al(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Na(1) and two equivalent Al(1) atoms.