Ba2Cr3AlO7 crystallizes in the orthorhombic Pmmm space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing CrO5 square pyramids. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Al(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Cr(2) atoms to form a mixture of distorted face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Cr(1), and one Cr(2) atom to form a mixture of face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°.
Ba2Cr3AlO7 crystallizes in the orthorhombic Pmmm space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. Both Ba(1)-O(1) bond lengths are 2.87 Å. Both Ba(1)-O(2) bond lengths are 3.12 Å. Both Ba(1)-O(3) bond lengths are 3.07 Å. All Ba(1)-O(4) bond lengths are 2.76 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing CrO5 square pyramids. The Cr(1)-O(4) bond length is 2.10 Å. Both Cr(1)-O(2) bond lengths are 1.95 Å. Both Cr(1)-O(3) bond lengths are 2.02 Å. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Both Cr(2)-O(1) bond lengths are 1.98 Å. Both Cr(2)-O(4) bond lengths are 2.08 Å. Al(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. All Al(1)-O(2) bond lengths are 2.34 Å. All Al(1)-O(3) bond lengths are 2.28 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Cr(2) atoms to form a mixture of distorted face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Cr(1), and one Cr(2) atom to form a mixture of face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°.