Sr7Mn4O15 crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to one O(2), one O(3), one O(4), one O(6), one O(7), one O(8), two equivalent O(1), and two equivalent O(5) atoms. In the second Sr site, Sr(2) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. In the third Sr site, Sr(3) is bonded in a 10-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(8), two equivalent O(6), and two equivalent O(7) atoms. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one O(4), one O(5), one O(6), one O(8), two equivalent O(1), and two equivalent O(2) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form a mixture of face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 15°. In the second Mn site, Mn(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form a mixture of face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Mn(1), and one Mn(2) atom. In the second O site, O(5) is bonded in a 6-coordinate geometry to one Sr(3), one Sr(4), two equivalent Sr(1), one Mn(1), and one Mn(2) atom. In the third O site, O(6) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(4), two equivalent Sr(3), and one Mn(2) atom. In the fourth O site, O(7) is bonded to one Sr(1), one Sr(2), two equivalent Sr(3), one Mn(1), and one Mn(2) atom to form a mixture of distorted face and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the fifth O site, O(8) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Mn(1), and one Mn(2) atom to form a mixture of distorted face and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the sixth O site, O(1) is bonded in a 6-coordinate geometry to one Sr(3), two equivalent Sr(1), two equivalent Sr(4), and one Mn(1) atom. In the seventh O site, O(2) is bonded in a 1-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), two equivalent Sr(4), and one Mn(1) atom. In the eighth O site, O(3) is bonded in a distorted linear geometry to two equivalent Sr(1), two equivalent Sr(3), and two equivalent Mn(2) atoms.
Sr7Mn4O15 crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to one O(2), one O(3), one O(4), one O(6), one O(7), one O(8), two equivalent O(1), and two equivalent O(5) atoms. The Sr(1)-O(2) bond length is 3.11 Å. The Sr(1)-O(3) bond length is 2.75 Å. The Sr(1)-O(4) bond length is 2.55 Å. The Sr(1)-O(6) bond length is 2.83 Å. The Sr(1)-O(7) bond length is 2.60 Å. The Sr(1)-O(8) bond length is 2.66 Å. There is one shorter (2.85 Å) and one longer (2.86 Å) Sr(1)-O(1) bond length. There is one shorter (2.53 Å) and one longer (3.03 Å) Sr(1)-O(5) bond length. In the second Sr site, Sr(2) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(4), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. Both Sr(2)-O(2) bond lengths are 2.62 Å. Both Sr(2)-O(4) bond lengths are 3.03 Å. Both Sr(2)-O(6) bond lengths are 2.74 Å. Both Sr(2)-O(7) bond lengths are 2.79 Å. Both Sr(2)-O(8) bond lengths are 2.70 Å. In the third Sr site, Sr(3) is bonded in a 10-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(8), two equivalent O(6), and two equivalent O(7) atoms. The Sr(3)-O(1) bond length is 2.46 Å. The Sr(3)-O(2) bond length is 2.81 Å. The Sr(3)-O(3) bond length is 2.71 Å. The Sr(3)-O(4) bond length is 2.70 Å. The Sr(3)-O(5) bond length is 2.69 Å. The Sr(3)-O(8) bond length is 2.64 Å. There is one shorter (2.70 Å) and one longer (2.83 Å) Sr(3)-O(6) bond length. There is one shorter (2.64 Å) and one longer (2.69 Å) Sr(3)-O(7) bond length. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one O(4), one O(5), one O(6), one O(8), two equivalent O(1), and two equivalent O(2) atoms. The Sr(4)-O(4) bond length is 2.64 Å. The Sr(4)-O(5) bond length is 2.62 Å. The Sr(4)-O(6) bond length is 2.42 Å. The Sr(4)-O(8) bond length is 2.52 Å. There is one shorter (2.63 Å) and one longer (2.71 Å) Sr(4)-O(1) bond length. There is one shorter (2.45 Å) and one longer (2.57 Å) Sr(4)-O(2) bond length. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form a mixture of face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 15°. The Mn(1)-O(1) bond length is 1.84 Å. The Mn(1)-O(2) bond length is 1.82 Å. The Mn(1)-O(4) bond length is 1.86 Å. The Mn(1)-O(5) bond length is 1.92 Å. The Mn(1)-O(7) bond length is 2.00 Å. The Mn(1)-O(8) bond length is 2.05 Å. In the second Mn site, Mn(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form a mixture of face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. The Mn(2)-O(3) bond length is 1.87 Å. The Mn(2)-O(4) bond length is 1.85 Å. The Mn(2)-O(5) bond length is 2.01 Å. The Mn(2)-O(6) bond length is 1.82 Å. The Mn(2)-O(7) bond length is 1.93 Å. The Mn(2)-O(8) bond length is 1.92 Å. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Mn(1), and one Mn(2) atom. In the second O site, O(5) is bonded in a 6-coordinate geometry to one Sr(3), one Sr(4), two equivalent Sr(1), one Mn(1), and one Mn(2) atom. In the third O site, O(6) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(4), two equivalent Sr(3), and one Mn(2) atom. In the fourth O site, O(7) is bonded to one Sr(1), one Sr(2), two equivalent Sr(3), one Mn(1), and one Mn(2) atom to form a mixture of distorted face and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the fifth O site, O(8) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Mn(1), and one Mn(2) atom to form a mixture of distorted face and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the sixth O site, O(1) is bonded in a 6-coordinate geometry to one Sr(3), two equivalent Sr(1), two equivalent Sr(4), and one Mn(1) atom. In the seventh O site, O(2) is bonded in a 1-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), two equivalent Sr(4), and one Mn(1) atom. In the eighth O site, O(3) is bonded in a distorted linear geometry to two equivalent Sr(1), two equivalent Sr(3), and two equivalent Mn(2) atoms.