Sr7Mn7O20 crystallizes in the monoclinic P2/m space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(10), one O(6), two equivalent O(1), two equivalent O(11), two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Sr(3)O12 cuboctahedra, corners with four equivalent Sr(2)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra, faces with three equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Mn(2)O6 octahedra, faces with four equivalent Mn(1)O6 octahedra, and faces with two equivalent Mn(3)O5 square pyramids. In the second Sr site, Sr(2) is bonded to one O(1), one O(10), one O(6), one O(9), two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(8) atoms to form SrO12 cuboctahedra that share  a cornercorner with one Sr(2)O12 cuboctahedra, corners with two equivalent Sr(3)O12 cuboctahedra, corners with four equivalent Sr(1)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Mn(1)O6 octahedra, faces with two equivalent Mn(2)O6 octahedra, faces with two equivalent Mn(4)O6 octahedra, and faces with two equivalent Mn(3)O5 square pyramids. In the third Sr site, Sr(3) is bonded to two equivalent O(1), two equivalent O(6), four equivalent O(2), and four equivalent O(7) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, corners with six equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, faces with four equivalent Mn(1)O6 octahedra, and faces with four equivalent Mn(2)O6 octahedra. In the fourth Sr site, Sr(4) is bonded in a distorted q6 geometry to one O(6), one O(9), two equivalent O(10), two equivalent O(3), two equivalent O(4), and two equivalent O(8) atoms. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(11), one O(2), one O(5), one O(7), and two equivalent O(1) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), one O(4), one O(7), and two equivalent O(6) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with two equivalent Sr(3)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-11°. In the third Mn site, Mn(3) is bonded to one O(4), one O(5), one O(8), and two equivalent O(10) atoms to form MnO5 square pyramids that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Mn(3)O5 square pyramids, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-17°. In the fourth Mn site, Mn(4) is bonded to two equivalent O(3), two equivalent O(8), and two equivalent O(9) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(3)O5 square pyramids, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-11°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Sr(2), one Sr(3), two equivalent Sr(1), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Sr(2), two equivalent Sr(3), one Mn(1), and one Mn(2) atom. In the third O site, O(3) is bonded to two equivalent Sr(2), two equivalent Sr(4), one Mn(2), and one Mn(4) atom to form a mixture of distorted edge, face, and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Sr(1), two equivalent Sr(4), one Mn(2), and one Mn(3) atom. In the fifth O site, O(5) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Mn(1), and one Mn(3) atom to form a mixture of distorted edge and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-62°. In the sixth O site, O(6) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), and two equivalent Mn(2) atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), one Mn(1), and one Mn(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to two equivalent Sr(2), two equivalent Sr(4), one Mn(3), and one Mn(4) atom. In the ninth O site, O(9) is bonded to two equivalent Sr(2), two equivalent Sr(4), and two equivalent Mn(4) atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(4), and two equivalent Mn(3) atoms. In the eleventh O site, O(11) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Mn(1) atoms.
Sr7Mn7O20 crystallizes in the monoclinic P2/m space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(10), one O(6), two equivalent O(1), two equivalent O(11), two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Sr(3)O12 cuboctahedra, corners with four equivalent Sr(2)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra, faces with three equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Mn(2)O6 octahedra, faces with four equivalent Mn(1)O6 octahedra, and faces with two equivalent Mn(3)O5 square pyramids. The Sr(1)-O(10) bond length is 3.04 Å. The Sr(1)-O(6) bond length is 2.81 Å. There is one shorter (2.68 Å) and one longer (2.77 Å) Sr(1)-O(1) bond length. Both Sr(1)-O(11) bond lengths are 2.74 Å. Both Sr(1)-O(4) bond lengths are 2.99 Å. Both Sr(1)-O(5) bond lengths are 2.77 Å. Both Sr(1)-O(7) bond lengths are 2.62 Å. In the second Sr site, Sr(2) is bonded to one O(1), one O(10), one O(6), one O(9), two equivalent O(2), two equivalent O(3), two equivalent O(5), and two equivalent O(8) atoms to form SrO12 cuboctahedra that share  a cornercorner with one Sr(2)O12 cuboctahedra, corners with two equivalent Sr(3)O12 cuboctahedra, corners with four equivalent Sr(1)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Mn(1)O6 octahedra, faces with two equivalent Mn(2)O6 octahedra, faces with two equivalent Mn(4)O6 octahedra, and faces with two equivalent Mn(3)O5 square pyramids. The Sr(2)-O(1) bond length is 2.76 Å. The Sr(2)-O(10) bond length is 3.02 Å. The Sr(2)-O(6) bond length is 2.67 Å. The Sr(2)-O(9) bond length is 2.79 Å. Both Sr(2)-O(2) bond lengths are 2.81 Å. Both Sr(2)-O(3) bond lengths are 2.61 Å. Both Sr(2)-O(5) bond lengths are 2.75 Å. Both Sr(2)-O(8) bond lengths are 2.97 Å. In the third Sr site, Sr(3) is bonded to two equivalent O(1), two equivalent O(6), four equivalent O(2), and four equivalent O(7) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, corners with six equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, faces with four equivalent Mn(1)O6 octahedra, and faces with four equivalent Mn(2)O6 octahedra. Both Sr(3)-O(1) bond lengths are 2.75 Å. Both Sr(3)-O(6) bond lengths are 2.79 Å. All Sr(3)-O(2) bond lengths are 2.69 Å. All Sr(3)-O(7) bond lengths are 2.84 Å. In the fourth Sr site, Sr(4) is bonded in a distorted q6 geometry to one O(6), one O(9), two equivalent O(10), two equivalent O(3), two equivalent O(4), and two equivalent O(8) atoms. The Sr(4)-O(6) bond length is 2.62 Å. The Sr(4)-O(9) bond length is 2.63 Å. There is one shorter (2.69 Å) and one longer (2.70 Å) Sr(4)-O(10) bond length. Both Sr(4)-O(3) bond lengths are 2.75 Å. Both Sr(4)-O(4) bond lengths are 2.61 Å. Both Sr(4)-O(8) bond lengths are 2.61 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(11), one O(2), one O(5), one O(7), and two equivalent O(1) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-8°. The Mn(1)-O(11) bond length is 1.93 Å. The Mn(1)-O(2) bond length is 1.94 Å. The Mn(1)-O(5) bond length is 1.98 Å. The Mn(1)-O(7) bond length is 2.05 Å. Both Mn(1)-O(1) bond lengths are 1.94 Å. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), one O(4), one O(7), and two equivalent O(6) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with two equivalent Sr(3)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-11°. The Mn(2)-O(2) bond length is 1.94 Å. The Mn(2)-O(3) bond length is 2.02 Å. The Mn(2)-O(4) bond length is 1.98 Å. The Mn(2)-O(7) bond length is 1.90 Å. Both Mn(2)-O(6) bond lengths are 1.94 Å. In the third Mn site, Mn(3) is bonded to one O(4), one O(5), one O(8), and two equivalent O(10) atoms to form MnO5 square pyramids that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Mn(3)O5 square pyramids, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-17°. The Mn(3)-O(4) bond length is 1.92 Å. The Mn(3)-O(5) bond length is 1.91 Å. The Mn(3)-O(8) bond length is 1.92 Å. Both Mn(3)-O(10) bond lengths are 1.97 Å. In the fourth Mn site, Mn(4) is bonded to two equivalent O(3), two equivalent O(8), and two equivalent O(9) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(3)O5 square pyramids, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-11°. Both Mn(4)-O(3) bond lengths are 1.94 Å. Both Mn(4)-O(8) bond lengths are 1.99 Å. Both Mn(4)-O(9) bond lengths are 1.94 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Sr(2), one Sr(3), two equivalent Sr(1), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Sr(2), two equivalent Sr(3), one Mn(1), and one Mn(2) atom. In the third O site, O(3) is bonded to two equivalent Sr(2), two equivalent Sr(4), one Mn(2), and one Mn(4) atom to form a mixture of distorted edge, face, and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Sr(1), two equivalent Sr(4), one Mn(2), and one Mn(3) atom. In the fifth O site, O(5) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Mn(1), and one Mn(3) atom to form a mixture of distorted edge and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-62°. In the sixth O site, O(6) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), and two equivalent Mn(2) atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), one Mn(1), and one Mn(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to two equivalent Sr(2), two equivalent Sr(4), one Mn(3), and one Mn(4) atom. In the ninth O site, O(9) is bonded to two equivalent Sr(2), two equivalent Sr(4), and two equivalent Mn(4) atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(4), and two equivalent Mn(3) atoms. In the eleventh O site, O(11) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Mn(1) atoms.