Cs2Al2Sb2O7 crystallizes in the trigonal P-3m1 space group. Cs(1) is bonded in a 9-coordinate geometry to nine equivalent O(1) atoms. Al(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing AlO4 tetrahedra. Sb(1) is bonded in a distorted T-shaped geometry to three equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to three equivalent Cs(1), one Al(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Al(1) atoms.
Cs2Al2Sb2O7 crystallizes in the trigonal P-3m1 space group. Cs(1) is bonded in a 9-coordinate geometry to nine equivalent O(1) atoms. There are six shorter (3.16 Å) and three longer (3.48 Å) Cs(1)-O(1) bond lengths. Al(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing AlO4 tetrahedra. The Al(1)-O(2) bond length is 1.73 Å. All Al(1)-O(1) bond lengths are 1.80 Å. Sb(1) is bonded in a distorted T-shaped geometry to three equivalent O(1) atoms. All Sb(1)-O(1) bond lengths are 1.98 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to three equivalent Cs(1), one Al(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Al(1) atoms.