Ca(Sn2O3)2 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form SnO5 square pyramids that share corners with four equivalent Sn(2)O6 octahedra, corners with two equivalent Sn(1)O5 square pyramids, edges with three equivalent Sn(2)O6 octahedra, and edges with three equivalent Sn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 25-84°. In the second Sn site, Sn(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted SnO6 octahedra that share corners with two equivalent Sn(2)O6 octahedra, corners with four equivalent Sn(1)O5 square pyramids, edges with two equivalent Sn(2)O6 octahedra, and edges with three equivalent Sn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-43°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sn(2) and four equivalent Sn(1) atoms to form OSn6 octahedra that share corners with eight equivalent O(3)CaSn4 square pyramids, corners with two equivalent O(4)Ca2Sn2 trigonal pyramids, edges with two equivalent O(1)Sn6 octahedra, edges with two equivalent O(3)CaSn4 square pyramids, and edges with four equivalent O(2)Ca2Sn3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Ca(1), one Sn(1), and two equivalent Sn(2) atoms to form distorted OCa2Sn3 trigonal bipyramids that share corners with four equivalent O(3)CaSn4 square pyramids, corners with two equivalent O(2)Ca2Sn3 trigonal bipyramids, corners with four equivalent O(4)Ca2Sn2 trigonal pyramids, edges with two equivalent O(1)Sn6 octahedra, edges with three equivalent O(3)CaSn4 square pyramids, edges with three equivalent O(2)Ca2Sn3 trigonal bipyramids, and  an edgeedge with one O(4)Ca2Sn2 trigonal pyramid. In the third O site, O(3) is bonded to one Ca(1), two equivalent Sn(1), and two equivalent Sn(2) atoms to form distorted OCaSn4 square pyramids that share corners with four equivalent O(1)Sn6 octahedra,  a cornercorner with one O(3)CaSn4 square pyramid, corners with four equivalent O(2)Ca2Sn3 trigonal bipyramids,  an edgeedge with one O(1)Sn6 octahedra, edges with two equivalent O(3)CaSn4 square pyramids, edges with three equivalent O(2)Ca2Sn3 trigonal bipyramids, and edges with two equivalent O(4)Ca2Sn2 trigonal pyramids. The corner-sharing octahedral tilt angles range from 9-81°. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Sn(2) atoms to form distorted OCa2Sn2 trigonal pyramids that share corners with two equivalent O(1)Sn6 octahedra, corners with eight equivalent O(2)Ca2Sn3 trigonal bipyramids, corners with two equivalent O(4)Ca2Sn2 trigonal pyramids, edges with four equivalent O(3)CaSn4 square pyramids, and edges with two equivalent O(2)Ca2Sn3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°.
Ca(Sn2O3)2 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. Both Ca(1)-O(3) bond lengths are 2.39 Å. Both Ca(1)-O(4) bond lengths are 2.42 Å. All Ca(1)-O(2) bond lengths are 2.72 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form SnO5 square pyramids that share corners with four equivalent Sn(2)O6 octahedra, corners with two equivalent Sn(1)O5 square pyramids, edges with three equivalent Sn(2)O6 octahedra, and edges with three equivalent Sn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 25-84°. The Sn(1)-O(2) bond length is 2.21 Å. Both Sn(1)-O(1) bond lengths are 2.50 Å. Both Sn(1)-O(3) bond lengths are 2.54 Å. In the second Sn site, Sn(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted SnO6 octahedra that share corners with two equivalent Sn(2)O6 octahedra, corners with four equivalent Sn(1)O5 square pyramids, edges with two equivalent Sn(2)O6 octahedra, and edges with three equivalent Sn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-43°. The Sn(2)-O(1) bond length is 2.69 Å. The Sn(2)-O(4) bond length is 2.09 Å. Both Sn(2)-O(2) bond lengths are 2.32 Å. Both Sn(2)-O(3) bond lengths are 2.27 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sn(2) and four equivalent Sn(1) atoms to form OSn6 octahedra that share corners with eight equivalent O(3)CaSn4 square pyramids, corners with two equivalent O(4)Ca2Sn2 trigonal pyramids, edges with two equivalent O(1)Sn6 octahedra, edges with two equivalent O(3)CaSn4 square pyramids, and edges with four equivalent O(2)Ca2Sn3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Ca(1), one Sn(1), and two equivalent Sn(2) atoms to form distorted OCa2Sn3 trigonal bipyramids that share corners with four equivalent O(3)CaSn4 square pyramids, corners with two equivalent O(2)Ca2Sn3 trigonal bipyramids, corners with four equivalent O(4)Ca2Sn2 trigonal pyramids, edges with two equivalent O(1)Sn6 octahedra, edges with three equivalent O(3)CaSn4 square pyramids, edges with three equivalent O(2)Ca2Sn3 trigonal bipyramids, and  an edgeedge with one O(4)Ca2Sn2 trigonal pyramid. In the third O site, O(3) is bonded to one Ca(1), two equivalent Sn(1), and two equivalent Sn(2) atoms to form distorted OCaSn4 square pyramids that share corners with four equivalent O(1)Sn6 octahedra,  a cornercorner with one O(3)CaSn4 square pyramid, corners with four equivalent O(2)Ca2Sn3 trigonal bipyramids,  an edgeedge with one O(1)Sn6 octahedra, edges with two equivalent O(3)CaSn4 square pyramids, edges with three equivalent O(2)Ca2Sn3 trigonal bipyramids, and edges with two equivalent O(4)Ca2Sn2 trigonal pyramids. The corner-sharing octahedral tilt angles range from 9-81°. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Sn(2) atoms to form distorted OCa2Sn2 trigonal pyramids that share corners with two equivalent O(1)Sn6 octahedra, corners with eight equivalent O(2)Ca2Sn3 trigonal bipyramids, corners with two equivalent O(4)Ca2Sn2 trigonal pyramids, edges with four equivalent O(3)CaSn4 square pyramids, and edges with two equivalent O(2)Ca2Sn3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°.