CaBiSbO5 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form CaO6 octahedra that share corners with four equivalent Sb(1)O4 tetrahedra and  an edgeedge with one Ca(1)O6 octahedra. Bi(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms. Sb(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form SbO4 tetrahedra that share corners with four equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-56°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Bi(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Bi(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1), one Bi(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Bi(1) atoms to form edge-sharing OCa2Bi2 tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Bi(1), and one Sb(1) atom.
CaBiSbO5 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form CaO6 octahedra that share corners with four equivalent Sb(1)O4 tetrahedra and  an edgeedge with one Ca(1)O6 octahedra. The Ca(1)-O(1) bond length is 2.42 Å. The Ca(1)-O(2) bond length is 2.39 Å. The Ca(1)-O(3) bond length is 2.29 Å. The Ca(1)-O(5) bond length is 2.33 Å. There is one shorter (2.40 Å) and one longer (2.48 Å) Ca(1)-O(4) bond length. Bi(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms. The Bi(1)-O(1) bond length is 2.42 Å. The Bi(1)-O(2) bond length is 2.44 Å. The Bi(1)-O(3) bond length is 2.80 Å. The Bi(1)-O(5) bond length is 2.48 Å. There is one shorter (2.16 Å) and one longer (2.30 Å) Bi(1)-O(4) bond length. Sb(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form SbO4 tetrahedra that share corners with four equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-56°. The Sb(1)-O(1) bond length is 1.91 Å. The Sb(1)-O(2) bond length is 1.91 Å. The Sb(1)-O(3) bond length is 1.90 Å. The Sb(1)-O(5) bond length is 1.92 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Bi(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Bi(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1), one Bi(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Bi(1) atoms to form edge-sharing OCa2Bi2 tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Bi(1), and one Sb(1) atom.