Sr3MgCr2S2O5 crystallizes in the tetragonal I-4m2 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Cr(1)O5 square pyramids. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent S(1), two equivalent O(1), and two equivalent O(2) atoms. In the third Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent S(1), two equivalent O(1), and two equivalent O(2) atoms. Mg(1) is bonded to four equivalent S(1) atoms to form corner-sharing MgS4 tetrahedra. Cr(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form CrO5 square pyramids that share corners with five equivalent Cr(1)O5 square pyramids and faces with four equivalent Sr(1)O12 cuboctahedra. S(1) is bonded in a 6-coordinate geometry to four equivalent Sr(2) and two equivalent Mg(1) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cr(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Cr(1) atoms.
Sr3MgCr2S2O5 crystallizes in the tetragonal I-4m2 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Cr(1)O5 square pyramids. All Sr(1)-O(1) bond lengths are 2.92 Å. All Sr(1)-O(2) bond lengths are 2.93 Å. All Sr(1)-O(3) bond lengths are 2.80 Å. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent S(1), two equivalent O(1), and two equivalent O(2) atoms. All Sr(2)-S(1) bond lengths are 3.18 Å. Both Sr(2)-O(1) bond lengths are 2.53 Å. Both Sr(2)-O(2) bond lengths are 2.52 Å. In the third Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent S(1), two equivalent O(1), and two equivalent O(2) atoms. All Sr(2)-S(1) bond lengths are 3.18 Å. Both Sr(2)-O(1) bond lengths are 2.53 Å. Both Sr(2)-O(2) bond lengths are 2.52 Å. Mg(1) is bonded to four equivalent S(1) atoms to form corner-sharing MgS4 tetrahedra. All Mg(1)-S(1) bond lengths are 2.51 Å. Cr(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form CrO5 square pyramids that share corners with five equivalent Cr(1)O5 square pyramids and faces with four equivalent Sr(1)O12 cuboctahedra. The Cr(1)-O(3) bond length is 1.91 Å. Both Cr(1)-O(1) bond lengths are 2.00 Å. Both Cr(1)-O(2) bond lengths are 2.00 Å. S(1) is bonded in a 6-coordinate geometry to four equivalent Sr(2) and two equivalent Mg(1) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cr(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Cr(1) atoms.