Ba2Sb2O5 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(3), two equivalent O(1), and four equivalent O(2) atoms to form distorted BaO7 pentagonal bipyramids that share corners with two equivalent Sb(1)O4 trigonal pyramids, edges with two equivalent Ba(1)O7 pentagonal bipyramids, and  an edgeedge with one Sb(1)O4 trigonal pyramid. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted SbO4 trigonal pyramids that share corners with two equivalent Ba(1)O7 pentagonal bipyramids, corners with two equivalent Sb(1)O4 trigonal pyramids, and  an edgeedge with one Ba(1)O7 pentagonal bipyramid. In the second Sb site, Sb(2) is bonded in an L-shaped geometry to two equivalent O(2) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), two equivalent Ba(2), and one Sb(1) atom to form a mixture of distorted corner and edge-sharing OBa3Sb tetrahedra. In the second O site, O(2) is bonded to one Ba(2), two equivalent Ba(1), and one Sb(2) atom to form a mixture of distorted corner and edge-sharing OBa3Sb tetrahedra. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1) and two equivalent Sb(1) atoms.
Ba2Sb2O5 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(3), two equivalent O(1), and four equivalent O(2) atoms to form distorted BaO7 pentagonal bipyramids that share corners with two equivalent Sb(1)O4 trigonal pyramids, edges with two equivalent Ba(1)O7 pentagonal bipyramids, and  an edgeedge with one Sb(1)O4 trigonal pyramid. The Ba(1)-O(3) bond length is 2.94 Å. Both Ba(1)-O(1) bond lengths are 2.87 Å. All Ba(1)-O(2) bond lengths are 2.72 Å. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Both Ba(2)-O(2) bond lengths are 2.81 Å. All Ba(2)-O(1) bond lengths are 2.71 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted SbO4 trigonal pyramids that share corners with two equivalent Ba(1)O7 pentagonal bipyramids, corners with two equivalent Sb(1)O4 trigonal pyramids, and  an edgeedge with one Ba(1)O7 pentagonal bipyramid. Both Sb(1)-O(1) bond lengths are 1.95 Å. Both Sb(1)-O(3) bond lengths are 2.12 Å. In the second Sb site, Sb(2) is bonded in an L-shaped geometry to two equivalent O(2) atoms. Both Sb(2)-O(2) bond lengths are 1.96 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), two equivalent Ba(2), and one Sb(1) atom to form a mixture of distorted corner and edge-sharing OBa3Sb tetrahedra. In the second O site, O(2) is bonded to one Ba(2), two equivalent Ba(1), and one Sb(2) atom to form a mixture of distorted corner and edge-sharing OBa3Sb tetrahedra. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1) and two equivalent Sb(1) atoms.