Ca2AlSbO5 crystallizes in the monoclinic Cc space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(4), two equivalent O(5), and three equivalent O(2) atoms. In the second Ca site, Ca(2) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form distorted CaO4 trigonal pyramids that share corners with four equivalent Al(1)O4 tetrahedra and corners with two equivalent Ca(2)O4 trigonal pyramids. Al(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with four equivalent Ca(2)O4 trigonal pyramids. Sb(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(2), and two equivalent Al(1) atoms to form distorted OCa2Al2 trigonal pyramids that share corners with two equivalent O(4)Ca2Sb2 tetrahedra and corners with two equivalent O(1)Ca2Al2 trigonal pyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Al(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Ca(2) and one Al(1) atom. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(2), and two equivalent Sb(1) atoms to form OCa2Sb2 tetrahedra that share corners with two equivalent O(4)Ca2Sb2 tetrahedra and corners with two equivalent O(1)Ca2Al2 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Sb(1) atoms.
Ca2AlSbO5 crystallizes in the monoclinic Cc space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(4), two equivalent O(5), and three equivalent O(2) atoms. The Ca(1)-O(1) bond length is 2.52 Å. The Ca(1)-O(4) bond length is 2.32 Å. There is one shorter (2.27 Å) and one longer (2.39 Å) Ca(1)-O(5) bond length. There are a spread of Ca(1)-O(2) bond distances ranging from 2.36-2.94 Å. In the second Ca site, Ca(2) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form distorted CaO4 trigonal pyramids that share corners with four equivalent Al(1)O4 tetrahedra and corners with two equivalent Ca(2)O4 trigonal pyramids. The Ca(2)-O(1) bond length is 2.45 Å. The Ca(2)-O(4) bond length is 2.42 Å. There is one shorter (2.23 Å) and one longer (2.32 Å) Ca(2)-O(3) bond length. Al(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with four equivalent Ca(2)O4 trigonal pyramids. The Al(1)-O(2) bond length is 1.83 Å. The Al(1)-O(3) bond length is 1.75 Å. There is one shorter (1.85 Å) and one longer (1.86 Å) Al(1)-O(1) bond length. Sb(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(4), and two equivalent O(5) atoms. The Sb(1)-O(2) bond length is 2.12 Å. There is one shorter (2.10 Å) and one longer (2.40 Å) Sb(1)-O(4) bond length. There is one shorter (2.03 Å) and one longer (2.33 Å) Sb(1)-O(5) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(2), and two equivalent Al(1) atoms to form distorted OCa2Al2 trigonal pyramids that share corners with two equivalent O(4)Ca2Sb2 tetrahedra and corners with two equivalent O(1)Ca2Al2 trigonal pyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Al(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Ca(2) and one Al(1) atom. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(2), and two equivalent Sb(1) atoms to form OCa2Sb2 tetrahedra that share corners with two equivalent O(4)Ca2Sb2 tetrahedra and corners with two equivalent O(1)Ca2Al2 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Sb(1) atoms.