SrMgFeO3 crystallizes in the monoclinic Cm space group. Sr(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Mg(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Fe(1)O5 trigonal bipyramid, corners with four equivalent Mg(1)O5 trigonal bipyramids, and edges with four equivalent Fe(1)O5 trigonal bipyramids. Fe(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with four equivalent Fe(1)O5 trigonal bipyramids, and edges with four equivalent Mg(1)O5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Fe(1) atoms to form distorted OSr2Mg2Fe2 octahedra that share corners with two equivalent O(1)Sr2Mg2Fe2 octahedra, corners with two equivalent O(3)Sr2Mg2Fe2 octahedra, corners with six equivalent O(2)Sr4MgFe octahedra, edges with two equivalent O(1)Sr2Mg2Fe2 octahedra, edges with five equivalent O(3)Sr2Mg2Fe2 octahedra, and faces with two equivalent O(2)Sr4MgFe octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Mg(1), and one Fe(1) atom to form distorted OSr4MgFe octahedra that share corners with four equivalent O(2)Sr4MgFe octahedra, corners with six equivalent O(1)Sr2Mg2Fe2 octahedra, corners with six equivalent O(3)Sr2Mg2Fe2 octahedra, edges with four equivalent O(2)Sr4MgFe octahedra, faces with two equivalent O(1)Sr2Mg2Fe2 octahedra, and faces with two equivalent O(3)Sr2Mg2Fe2 octahedra. The corner-sharing octahedral tilt angles range from 3-69°. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Fe(1) atoms to form OSr2Mg2Fe2 octahedra that share corners with two equivalent O(1)Sr2Mg2Fe2 octahedra, corners with two equivalent O(3)Sr2Mg2Fe2 octahedra, corners with six equivalent O(2)Sr4MgFe octahedra, edges with two equivalent O(3)Sr2Mg2Fe2 octahedra, edges with five equivalent O(1)Sr2Mg2Fe2 octahedra, and faces with two equivalent O(2)Sr4MgFe octahedra. The corner-sharing octahedral tilt angles range from 0-68°.
SrMgFeO3 crystallizes in the monoclinic Cm space group. Sr(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. There is one shorter (2.67 Å) and one longer (2.77 Å) Sr(1)-O(1) bond length. There is one shorter (2.65 Å) and one longer (2.66 Å) Sr(1)-O(3) bond length. There are two shorter (2.68 Å) and two longer (2.77 Å) Sr(1)-O(2) bond lengths. Mg(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Fe(1)O5 trigonal bipyramid, corners with four equivalent Mg(1)O5 trigonal bipyramids, and edges with four equivalent Fe(1)O5 trigonal bipyramids. The Mg(1)-O(2) bond length is 2.02 Å. There is one shorter (2.04 Å) and one longer (2.05 Å) Mg(1)-O(1) bond length. Both Mg(1)-O(3) bond lengths are 2.15 Å. Fe(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with four equivalent Fe(1)O5 trigonal bipyramids, and edges with four equivalent Mg(1)O5 trigonal bipyramids. The Fe(1)-O(2) bond length is 2.00 Å. Both Fe(1)-O(1) bond lengths are 2.15 Å. There is one shorter (2.12 Å) and one longer (2.17 Å) Fe(1)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Fe(1) atoms to form distorted OSr2Mg2Fe2 octahedra that share corners with two equivalent O(1)Sr2Mg2Fe2 octahedra, corners with two equivalent O(3)Sr2Mg2Fe2 octahedra, corners with six equivalent O(2)Sr4MgFe octahedra, edges with two equivalent O(1)Sr2Mg2Fe2 octahedra, edges with five equivalent O(3)Sr2Mg2Fe2 octahedra, and faces with two equivalent O(2)Sr4MgFe octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Mg(1), and one Fe(1) atom to form distorted OSr4MgFe octahedra that share corners with four equivalent O(2)Sr4MgFe octahedra, corners with six equivalent O(1)Sr2Mg2Fe2 octahedra, corners with six equivalent O(3)Sr2Mg2Fe2 octahedra, edges with four equivalent O(2)Sr4MgFe octahedra, faces with two equivalent O(1)Sr2Mg2Fe2 octahedra, and faces with two equivalent O(3)Sr2Mg2Fe2 octahedra. The corner-sharing octahedral tilt angles range from 3-69°. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Fe(1) atoms to form OSr2Mg2Fe2 octahedra that share corners with two equivalent O(1)Sr2Mg2Fe2 octahedra, corners with two equivalent O(3)Sr2Mg2Fe2 octahedra, corners with six equivalent O(2)Sr4MgFe octahedra, edges with two equivalent O(3)Sr2Mg2Fe2 octahedra, edges with five equivalent O(1)Sr2Mg2Fe2 octahedra, and faces with two equivalent O(2)Sr4MgFe octahedra. The corner-sharing octahedral tilt angles range from 0-68°.