CaSb4O9 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(5), two equivalent O(3), and two equivalent O(8) atoms to form distorted edge-sharing SbO5 square pyramids. In the second Sb site, Sb(2) is bonded in a 3-coordinate geometry to one O(5), one O(6), and one O(8) atom. In the third Sb site, Sb(3) is bonded to one O(1), one O(2), one O(7), and two equivalent O(9) atoms to form a mixture of distorted corner and edge-sharing SbO5 trigonal bipyramids. In the fourth Sb site, Sb(4) is bonded to one O(1), one O(4), one O(6), and two equivalent O(7) atoms to form a mixture of distorted corner and edge-sharing SbO5 trigonal bipyramids. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Sb(3) and one Sb(4) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ca(1) and one Sb(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1) and two equivalent Sb(1) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ca(1) and one Sb(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Sb(1), and one Sb(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ca(1), one Sb(2), and one Sb(4) atom. In the seventh O site, O(7) is bonded to one Ca(1), one Sb(3), and two equivalent Sb(4) atoms to form a mixture of distorted corner and edge-sharing OCaSb3 tetrahedra. In the eighth O site, O(8) is bonded to one Ca(1), one Sb(2), and two equivalent Sb(1) atoms to form a mixture of distorted corner and edge-sharing OCaSb3 trigonal pyramids. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1) and two equivalent Sb(3) atoms.
CaSb4O9 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Ca(1)-O(2) bond length is 2.33 Å. The Ca(1)-O(3) bond length is 2.72 Å. The Ca(1)-O(4) bond length is 2.39 Å. The Ca(1)-O(5) bond length is 2.36 Å. The Ca(1)-O(6) bond length is 2.87 Å. The Ca(1)-O(7) bond length is 2.76 Å. The Ca(1)-O(8) bond length is 2.41 Å. The Ca(1)-O(9) bond length is 2.58 Å. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(5), two equivalent O(3), and two equivalent O(8) atoms to form distorted edge-sharing SbO5 square pyramids. The Sb(1)-O(5) bond length is 2.20 Å. There is one shorter (2.05 Å) and one longer (2.12 Å) Sb(1)-O(3) bond length. There is one shorter (2.28 Å) and one longer (2.47 Å) Sb(1)-O(8) bond length. In the second Sb site, Sb(2) is bonded in a 3-coordinate geometry to one O(5), one O(6), and one O(8) atom. The Sb(2)-O(5) bond length is 1.97 Å. The Sb(2)-O(6) bond length is 2.07 Å. The Sb(2)-O(8) bond length is 2.01 Å. In the third Sb site, Sb(3) is bonded to one O(1), one O(2), one O(7), and two equivalent O(9) atoms to form a mixture of distorted corner and edge-sharing SbO5 trigonal bipyramids. The Sb(3)-O(1) bond length is 1.96 Å. The Sb(3)-O(2) bond length is 1.84 Å. The Sb(3)-O(7) bond length is 2.22 Å. There is one shorter (1.99 Å) and one longer (2.04 Å) Sb(3)-O(9) bond length. In the fourth Sb site, Sb(4) is bonded to one O(1), one O(4), one O(6), and two equivalent O(7) atoms to form a mixture of distorted corner and edge-sharing SbO5 trigonal bipyramids. The Sb(4)-O(1) bond length is 2.01 Å. The Sb(4)-O(4) bond length is 1.85 Å. The Sb(4)-O(6) bond length is 1.93 Å. There is one shorter (2.10 Å) and one longer (2.14 Å) Sb(4)-O(7) bond length. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Sb(3) and one Sb(4) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ca(1) and one Sb(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1) and two equivalent Sb(1) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ca(1) and one Sb(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Sb(1), and one Sb(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ca(1), one Sb(2), and one Sb(4) atom. In the seventh O site, O(7) is bonded to one Ca(1), one Sb(3), and two equivalent Sb(4) atoms to form a mixture of distorted corner and edge-sharing OCaSb3 tetrahedra. In the eighth O site, O(8) is bonded to one Ca(1), one Sb(2), and two equivalent Sb(1) atoms to form a mixture of distorted corner and edge-sharing OCaSb3 trigonal pyramids. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1) and two equivalent Sb(3) atoms.