Sr4MgFe4O11 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one Mg(1), one O(5), two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms. In the second Sr site, Sr(2) is bonded in a 11-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the fourth Sr site, Sr(4) is bonded in a 12-coordinate geometry to one O(6), one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. Mg(1) is bonded in a distorted square co-planar geometry to one Sr(1), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 19-31°. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Fe(1), and one Fe(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Mg(1), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Mg(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Fe(1), and one Fe(2) atom. In the fifth O site, O(5) is bonded to one Sr(1), one Sr(2), two equivalent Sr(4), and two equivalent Fe(2) atoms to form distorted OSr4Fe2 octahedra that share corners with two equivalent O(5)Sr4Fe2 octahedra and edges with two equivalent O(6)Sr3Fe2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the sixth O site, O(6) is bonded to one Sr(4), two equivalent Sr(1), and two equivalent Fe(1) atoms to form distorted OSr3Fe2 trigonal bipyramids that share corners with two equivalent O(6)Sr3Fe2 trigonal bipyramids and edges with two equivalent O(5)Sr4Fe2 octahedra. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Sr(3), one Sr(4), two equivalent Sr(2), and two equivalent Fe(1) atoms.
Sr4MgFe4O11 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one Mg(1), one O(5), two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms. The Sr(1)-Mg(1) bond length is 2.44 Å. The Sr(1)-O(5) bond length is 2.43 Å. Both Sr(1)-O(1) bond lengths are 2.64 Å. Both Sr(1)-O(4) bond lengths are 2.63 Å. There is one shorter (2.79 Å) and one longer (2.82 Å) Sr(1)-O(6) bond length. In the second Sr site, Sr(2) is bonded in a 11-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms. The Sr(2)-O(5) bond length is 2.73 Å. Both Sr(2)-O(1) bond lengths are 2.68 Å. Both Sr(2)-O(2) bond lengths are 3.21 Å. Both Sr(2)-O(3) bond lengths are 3.21 Å. Both Sr(2)-O(4) bond lengths are 2.70 Å. There is one shorter (2.81 Å) and one longer (2.82 Å) Sr(2)-O(7) bond length. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Sr(3)-O(7) bond length is 3.07 Å. Both Sr(3)-O(1) bond lengths are 2.60 Å. Both Sr(3)-O(2) bond lengths are 2.67 Å. Both Sr(3)-O(3) bond lengths are 2.67 Å. Both Sr(3)-O(4) bond lengths are 2.60 Å. In the fourth Sr site, Sr(4) is bonded in a 12-coordinate geometry to one O(6), one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. The Sr(4)-O(6) bond length is 2.56 Å. The Sr(4)-O(7) bond length is 2.50 Å. Both Sr(4)-O(1) bond lengths are 3.05 Å. Both Sr(4)-O(2) bond lengths are 3.13 Å. Both Sr(4)-O(3) bond lengths are 3.15 Å. Both Sr(4)-O(4) bond lengths are 3.03 Å. There is one shorter (2.79 Å) and one longer (2.80 Å) Sr(4)-O(5) bond length. Mg(1) is bonded in a distorted square co-planar geometry to one Sr(1), two equivalent O(2), and two equivalent O(3) atoms. Both Mg(1)-O(2) bond lengths are 2.00 Å. Both Mg(1)-O(3) bond lengths are 2.00 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 19-31°. The Fe(1)-O(1) bond length is 2.12 Å. The Fe(1)-O(2) bond length is 2.17 Å. The Fe(1)-O(3) bond length is 2.18 Å. The Fe(1)-O(4) bond length is 2.12 Å. The Fe(1)-O(6) bond length is 1.96 Å. The Fe(1)-O(7) bond length is 2.09 Å. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Fe(2)-O(1) bond length is 1.98 Å. The Fe(2)-O(2) bond length is 2.03 Å. The Fe(2)-O(3) bond length is 2.02 Å. The Fe(2)-O(4) bond length is 1.98 Å. The Fe(2)-O(5) bond length is 1.90 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Fe(1), and one Fe(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Mg(1), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Mg(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Fe(1), and one Fe(2) atom. In the fifth O site, O(5) is bonded to one Sr(1), one Sr(2), two equivalent Sr(4), and two equivalent Fe(2) atoms to form distorted OSr4Fe2 octahedra that share corners with two equivalent O(5)Sr4Fe2 octahedra and edges with two equivalent O(6)Sr3Fe2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the sixth O site, O(6) is bonded to one Sr(4), two equivalent Sr(1), and two equivalent Fe(1) atoms to form distorted OSr3Fe2 trigonal bipyramids that share corners with two equivalent O(6)Sr3Fe2 trigonal bipyramids and edges with two equivalent O(5)Sr4Fe2 octahedra. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Sr(3), one Sr(4), two equivalent Sr(2), and two equivalent Fe(1) atoms.