Mg2Sn2O5 crystallizes in the orthorhombic Pbam space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Sn(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing SnO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Mg(1) and two equivalent Sn(1) atoms to form OMg4Sn2 octahedra that share corners with eight equivalent O(2)Mg2Sn2 tetrahedra, edges with two equivalent O(1)Mg4Sn2 octahedra, edges with two equivalent O(2)Mg2Sn2 tetrahedra, and faces with four equivalent O(3)Mg2Sn2 trigonal pyramids. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Sn(1) atoms to form OMg2Sn2 tetrahedra that share corners with four equivalent O(1)Mg4Sn2 octahedra, corners with four equivalent O(2)Mg2Sn2 tetrahedra, corners with eight equivalent O(3)Mg2Sn2 trigonal pyramids, and  an edgeedge with one O(1)Mg4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 3-79°. In the third O site, O(3) is bonded to two equivalent Mg(1) and two equivalent Sn(1) atoms to form OMg2Sn2 trigonal pyramids that share corners with eight equivalent O(2)Mg2Sn2 tetrahedra, corners with two equivalent O(3)Mg2Sn2 trigonal pyramids,  an edgeedge with one O(3)Mg2Sn2 trigonal pyramid, and faces with two equivalent O(1)Mg4Sn2 octahedra.
Mg2Sn2O5 crystallizes in the orthorhombic Pbam space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Mg(1)-O(1) bond lengths are 2.41 Å. Both Mg(1)-O(2) bond lengths are 2.38 Å. There is one shorter (2.07 Å) and one longer (2.23 Å) Mg(1)-O(3) bond length. Sn(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing SnO5 square pyramids. The Sn(1)-O(1) bond length is 2.24 Å. There is one shorter (2.09 Å) and one longer (2.23 Å) Sn(1)-O(2) bond length. Both Sn(1)-O(3) bond lengths are 2.08 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Mg(1) and two equivalent Sn(1) atoms to form OMg4Sn2 octahedra that share corners with eight equivalent O(2)Mg2Sn2 tetrahedra, edges with two equivalent O(1)Mg4Sn2 octahedra, edges with two equivalent O(2)Mg2Sn2 tetrahedra, and faces with four equivalent O(3)Mg2Sn2 trigonal pyramids. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Sn(1) atoms to form OMg2Sn2 tetrahedra that share corners with four equivalent O(1)Mg4Sn2 octahedra, corners with four equivalent O(2)Mg2Sn2 tetrahedra, corners with eight equivalent O(3)Mg2Sn2 trigonal pyramids, and  an edgeedge with one O(1)Mg4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 3-79°. In the third O site, O(3) is bonded to two equivalent Mg(1) and two equivalent Sn(1) atoms to form OMg2Sn2 trigonal pyramids that share corners with eight equivalent O(2)Mg2Sn2 tetrahedra, corners with two equivalent O(3)Mg2Sn2 trigonal pyramids,  an edgeedge with one O(3)Mg2Sn2 trigonal pyramid, and faces with two equivalent O(1)Mg4Sn2 octahedra.