Ba2Cr2TlAlO7 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted BaO5 square pyramids that share corners with five equivalent Ba(1)O5 square pyramids, corners with four equivalent Cr(1)O5 trigonal bipyramids, and edges with four equivalent Ba(1)O5 square pyramids. Cr(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted CrO5 trigonal bipyramids that share corners with four equivalent Ba(1)O5 square pyramids and corners with four equivalent Cr(1)O5 trigonal bipyramids. Tl(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. Al(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and one Cr(1) atom to form distorted OBa4Cr square pyramids that share corners with four equivalent O(3)Ba2Tl4 octahedra, corners with four equivalent O(1)Ba4Cr square pyramids, and edges with four equivalent O(1)Ba4Cr square pyramids. The corner-sharing octahedral tilt angles are 83°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Cr(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded to two equivalent Ba(1) and four equivalent Tl(1) atoms to form OBa2Tl4 octahedra that share corners with four equivalent O(3)Ba2Tl4 octahedra, corners with eight equivalent O(1)Ba4Cr square pyramids, and edges with four equivalent O(3)Ba2Tl4 octahedra. The corner-sharing octahedra are not tilted.
Ba2Cr2TlAlO7 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted BaO5 square pyramids that share corners with five equivalent Ba(1)O5 square pyramids, corners with four equivalent Cr(1)O5 trigonal bipyramids, and edges with four equivalent Ba(1)O5 square pyramids. The Ba(1)-O(3) bond length is 2.64 Å. All Ba(1)-O(1) bond lengths are 2.73 Å. Cr(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted CrO5 trigonal bipyramids that share corners with four equivalent Ba(1)O5 square pyramids and corners with four equivalent Cr(1)O5 trigonal bipyramids. The Cr(1)-O(1) bond length is 1.94 Å. All Cr(1)-O(2) bond lengths are 1.97 Å. Tl(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. All Tl(1)-O(3) bond lengths are 2.71 Å. Al(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. All Al(1)-O(2) bond lengths are 2.28 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and one Cr(1) atom to form distorted OBa4Cr square pyramids that share corners with four equivalent O(3)Ba2Tl4 octahedra, corners with four equivalent O(1)Ba4Cr square pyramids, and edges with four equivalent O(1)Ba4Cr square pyramids. The corner-sharing octahedral tilt angles are 83°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Cr(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded to two equivalent Ba(1) and four equivalent Tl(1) atoms to form OBa2Tl4 octahedra that share corners with four equivalent O(3)Ba2Tl4 octahedra, corners with eight equivalent O(1)Ba4Cr square pyramids, and edges with four equivalent O(3)Ba2Tl4 octahedra. The corner-sharing octahedra are not tilted.