Ba3Al4(Sb2O7)3 crystallizes in the monoclinic C2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(6), one O(7), one O(9), and two equivalent O(1) atoms. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(5), and two equivalent O(8) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(11), one O(2), one O(5), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Sb(1)O4 tetrahedra and  an edgeedge with one Sb(1)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(10), one O(3), one O(6), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra and  a cornercorner with one Sb(1)O4 tetrahedra. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(11), one O(3), one O(5), and one O(9) atom to form SbO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra, and  an edgeedge with one Al(1)O4 tetrahedra. In the second Sb site, Sb(2) is bonded in a trigonal non-coplanar geometry to one O(2), one O(4), and one O(8) atom. In the third Sb site, Sb(3) is bonded in a distorted T-shaped geometry to one O(1), one O(6), and one O(7) atom. There are eleven inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Ba(1), one Al(2), and one Sb(3) atom. In the second O site, O(8) is bonded in a bent 120 degrees geometry to one Ba(2) and one Sb(2) atom. In the third O site, O(9) is bonded in a 2-coordinate geometry to one Ba(1), one Al(1), and one Sb(1) atom. In the fourth O site, O(10) is bonded in a linear geometry to two equivalent Al(2) atoms. In the fifth O site, O(11) is bonded in an L-shaped geometry to one Al(1) and one Sb(1) atom. In the sixth O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(1) and one Sb(3) atom. In the seventh O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Ba(2), one Al(1), and one Sb(2) atom. In the eighth O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Al(2), and one Sb(1) atom. In the ninth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ba(2), and one Sb(2) atom. In the tenth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Al(1), and one Sb(1) atom. In the eleventh O site, O(6) is bonded in a distorted trigonal planar geometry to one Ba(1), one Al(2), and one Sb(3) atom.
Ba3Al4(Sb2O7)3 crystallizes in the monoclinic C2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(6), one O(7), one O(9), and two equivalent O(1) atoms. The Ba(1)-O(3) bond length is 3.01 Å. The Ba(1)-O(4) bond length is 2.83 Å. The Ba(1)-O(6) bond length is 2.74 Å. The Ba(1)-O(7) bond length is 2.72 Å. The Ba(1)-O(9) bond length is 3.15 Å. There is one shorter (2.61 Å) and one longer (3.18 Å) Ba(1)-O(1) bond length. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(5), and two equivalent O(8) atoms. Both Ba(2)-O(2) bond lengths are 3.05 Å. Both Ba(2)-O(4) bond lengths are 2.84 Å. Both Ba(2)-O(5) bond lengths are 2.90 Å. Both Ba(2)-O(8) bond lengths are 2.70 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(11), one O(2), one O(5), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Sb(1)O4 tetrahedra and  an edgeedge with one Sb(1)O4 tetrahedra. The Al(1)-O(11) bond length is 1.87 Å. The Al(1)-O(2) bond length is 1.72 Å. The Al(1)-O(5) bond length is 1.85 Å. The Al(1)-O(9) bond length is 1.82 Å. In the second Al site, Al(2) is bonded to one O(10), one O(3), one O(6), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra and  a cornercorner with one Sb(1)O4 tetrahedra. The Al(2)-O(10) bond length is 1.71 Å. The Al(2)-O(3) bond length is 1.83 Å. The Al(2)-O(6) bond length is 1.77 Å. The Al(2)-O(7) bond length is 1.77 Å. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(11), one O(3), one O(5), and one O(9) atom to form SbO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra, and  an edgeedge with one Al(1)O4 tetrahedra. The Sb(1)-O(11) bond length is 1.94 Å. The Sb(1)-O(3) bond length is 1.88 Å. The Sb(1)-O(5) bond length is 1.94 Å. The Sb(1)-O(9) bond length is 1.90 Å. In the second Sb site, Sb(2) is bonded in a trigonal non-coplanar geometry to one O(2), one O(4), and one O(8) atom. The Sb(2)-O(2) bond length is 2.00 Å. The Sb(2)-O(4) bond length is 1.92 Å. The Sb(2)-O(8) bond length is 1.90 Å. In the third Sb site, Sb(3) is bonded in a distorted T-shaped geometry to one O(1), one O(6), and one O(7) atom. The Sb(3)-O(1) bond length is 1.92 Å. The Sb(3)-O(6) bond length is 2.02 Å. The Sb(3)-O(7) bond length is 2.00 Å. There are eleven inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Ba(1), one Al(2), and one Sb(3) atom. In the second O site, O(8) is bonded in a bent 120 degrees geometry to one Ba(2) and one Sb(2) atom. In the third O site, O(9) is bonded in a 2-coordinate geometry to one Ba(1), one Al(1), and one Sb(1) atom. In the fourth O site, O(10) is bonded in a linear geometry to two equivalent Al(2) atoms. In the fifth O site, O(11) is bonded in an L-shaped geometry to one Al(1) and one Sb(1) atom. In the sixth O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(1) and one Sb(3) atom. In the seventh O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Ba(2), one Al(1), and one Sb(2) atom. In the eighth O site, O(3) is bonded in a 2-coordinate geometry to one Ba(1), one Al(2), and one Sb(1) atom. In the ninth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ba(2), and one Sb(2) atom. In the tenth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Al(1), and one Sb(1) atom. In the eleventh O site, O(6) is bonded in a distorted trigonal planar geometry to one Ba(1), one Al(2), and one Sb(3) atom.