Sr2MnNbO6 crystallizes in the triclinic P1 space group. There are eight inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(11), one O(15), one O(16), one O(17), one O(19), one O(21), one O(24), one O(5), one O(8), one O(9), and two equivalent O(1) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Sr(2)O12 cuboctahedra, corners with three equivalent Sr(4)O12 cuboctahedra, corners with four equivalent Sr(3)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra, faces with two equivalent Sr(7)O12 cuboctahedra, faces with two equivalent Sr(8)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(3)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with two equivalent Mn(1)O6 octahedra. In the second Sr site, Sr(2) is bonded to one O(10), one O(12), one O(13), one O(16), one O(18), one O(20), one O(21), one O(22), one O(5), one O(6), and two equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(2)O12 cuboctahedra, corners with three equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Sr(3)O12 cuboctahedra, corners with four equivalent Sr(4)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra, faces with two equivalent Sr(5)O12 cuboctahedra, faces with two equivalent Sr(8)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(2)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Mn(3)O6 octahedra. In the third Sr site, Sr(3) is bonded to one O(11), one O(13), one O(14), one O(17), one O(19), one O(22), one O(23), one O(6), one O(7), one O(9), and two equivalent O(3) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(3)O12 cuboctahedra, corners with three equivalent Sr(2)O12 cuboctahedra, corners with three equivalent Sr(4)O12 cuboctahedra, corners with four equivalent Sr(1)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(5)O12 cuboctahedra, faces with two equivalent Sr(6)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(2)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Mn(4)O6 octahedra. In the fourth Sr site, Sr(4) is bonded to one O(10), one O(12), one O(14), one O(15), one O(18), one O(20), one O(23), one O(24), one O(7), one O(8), and two equivalent O(4) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(4)O12 cuboctahedra, corners with three 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(5)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(6)O12 cuboctahedra, faces with two equivalent Sr(7)O12 cuboctahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(3)O6 octahedra, faces with two equivalent Nb(4)O6 octahedra, and faces with two equivalent Mn(2)O6 octahedra. In the fifth Sr site, Sr(5) is bonded to one O(10), one O(17), one O(18), one O(2), one O(21), one O(23), one O(3), one O(5), one O(7), one O(9), and two equivalent O(13) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(5)O12 cuboctahedra, corners with three equivalent Sr(6)O12 cuboctahedra, corners with three equivalent Sr(8)O12 cuboctahedra, corners with four equivalent Sr(7)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Mn(3)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with two equivalent Mn(2)O6 octahedra. In the sixth Sr site, Sr(6) is bonded to one O(10), one O(11), one O(18), one O(19), one O(22), one O(24), one O(3), one O(4), one O(6), one O(8), and two equivalent O(14) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(6)O12 cuboctahedra, corners with three equivalent Sr(5)O12 cuboctahedra, corners with three equivalent Sr(7)O12 cuboctahedra, corners with four equivalent Sr(8)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(2)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Mn(1)O6 octahedra. In the seventh Sr site, Sr(7) is bonded to one O(1), one O(11), one O(12), one O(19), one O(20), one O(21), one O(23), one O(4), one O(5), one O(7), and two equivalent O(15) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(7)O12 cuboctahedra, corners with three equivalent Sr(6)O12 cuboctahedra, corners with three equivalent Sr(8)O12 cuboctahedra, corners with four equivalent Sr(5)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(2)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Mn(3)O6 octahedra. In the eighth Sr site, Sr(8) is bonded to one O(1), one O(12), one O(17), one O(2), one O(20), one O(22), one O(24), one O(6), one O(8), one O(9), and two equivalent O(16) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(8)O12 cuboctahedra, corners with three equivalent Sr(5)O12 cuboctahedra, corners with three equivalent Sr(7)O12 cuboctahedra, corners with four equivalent Sr(6)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(3)O6 octahedra, faces with two equivalent Nb(4)O6 octahedra, and faces with two equivalent Mn(4)O6 octahedra. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(13), one O(17), one O(21), one O(5), and one O(9) atom to form NbO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-8°. In the second Nb site, Nb(2) is bonded to one O(10), one O(14), one O(18), one O(2), one O(22), and one O(6) atom to form NbO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with two equivalent Sr(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-9°. In the third Nb site, Nb(3) is bonded to one O(11), one O(15), one O(19), one O(23), one O(3), and one O(7) atom to form NbO6 octahedra that share  a cornercorner with one Mn(3)O6 octahedra,  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 faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(7)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-8°. In the fourth Nb site, Nb(4) is bonded to one O(12), one O(16), one O(20), one O(24), one O(4), and one O(8) atom to form NbO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra, and faces with two equivalent Sr(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(14), one O(19), one O(24), and one O(8) atom to form MnO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(18), one O(23), one O(4), and one O(7) atom to form MnO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra, and faces with two equivalent Sr(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. In the third Mn site, Mn(3) is bonded to one O(12), one O(15), one O(2), one O(20), one O(21), and one O(5) atom to form MnO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with two equivalent Sr(7)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. In the fourth Mn site, Mn(4) is bonded to one O(16), one O(17), one O(22), one O(3), one O(6), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-9°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Sr(7), one Sr(8), two equivalent Sr(1), one Nb(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Sr(5), one Sr(8), two equivalent Sr(2), one Nb(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Sr(5), one Sr(6), two equivalent Sr(3), one Nb(3), and one Mn(4) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(6), one Sr(7), two equivalent Sr(4), one Nb(4), and one Mn(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), one Sr(5), one Sr(7), one Nb(1), and one Mn(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(6), one Sr(8), one Nb(2), and one Mn(4) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Sr(3), one Sr(4), one Sr(5), one Sr(7), one Nb(3), and one Mn(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(4), one Sr(6), one Sr(8), one Nb(4), and one Mn(1) atom. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Sr(1), one Sr(3), one Sr(5), one Sr(8), one Nb(1), and one Mn(4) atom. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Sr(2), one Sr(4), one Sr(5), one Sr(6), one Nb(2), and one Mn(2) atom. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Sr(1), one Sr(3), one Sr(6), one Sr(7), one Nb(3), and one Mn(1) atom. In the twelfth O site, O(12) is bonded in a distorted linear geometry to one Sr(2), one Sr(4), one Sr(7), one Sr(8), one Nb(4), and one Mn(3) atom. In the thirteenth O site, O(13) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), two equivalent Sr(5), one Nb(1), and one Mn(2) atom. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to one Sr(3), one Sr(4), two equivalent Sr(6), one Nb(2), and one Mn(1) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(4), two equivalent Sr(7), one Nb(3), and one Mn(3) atom. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(8), one Nb(4), and one Mn(4) atom. In the seventeenth O site, O(17) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(3), one Sr(5), one Sr(8), one Nb(1), and one Mn(4) atom. In the eighteenth O site, O(18) is bonded in a 2-coordinate geometry to one Sr(2), one Sr(4), one Sr(5), one Sr(6), one Nb(2), and one Mn(2) atom. In the nineteenth O site, O(19) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(3), one Sr(6), one Sr(7), one Nb(3), and one Mn(1) atom. In the twentieth O site, O(20) is bonded in a 2-coordinate geometry to one Sr(2), one Sr(4), one Sr(7), one Sr(8), one Nb(4), and one Mn(3) atom. In the twenty-first O site, O(21) is bonded in a distorted linear geometry to one Sr(1), one Sr(2), one Sr(5), one Sr(7), one Nb(1), and one Mn(3) atom. In the twenty-second O site, O(22) is bonded in a distorted linear geometry to one Sr(2), one Sr(3), one Sr(6), one Sr(8), one Nb(2), and one Mn(4) atom. In the twenty-third O site, O(23) is bonded in a distorted linear geometry to one Sr(3), one Sr(4), one Sr(5), one Sr(7), one Nb(3), and one Mn(2) atom. In the twenty-fourth O site, O(24) is bonded in a distorted linear geometry to one Sr(1), one Sr(4), one Sr(6), one Sr(8), one Nb(4), and one Mn(1) atom.
Sr2MnNbO6 crystallizes in the triclinic P1 space group. There are eight inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one O(11), one O(15), one O(16), one O(17), one O(19), one O(21), one O(24), one O(5), one O(8), one O(9), and two equivalent O(1) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Sr(2)O12 cuboctahedra, corners with three equivalent Sr(4)O12 cuboctahedra, corners with four equivalent Sr(3)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra, faces with two equivalent Sr(7)O12 cuboctahedra, faces with two equivalent Sr(8)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(3)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with two equivalent Mn(1)O6 octahedra. The Sr(1)-O(11) bond length is 3.03 Å. The Sr(1)-O(15) bond length is 3.00 Å. The Sr(1)-O(16) bond length is 3.02 Å. The Sr(1)-O(17) bond length is 2.76 Å. The Sr(1)-O(19) bond length is 2.92 Å. The Sr(1)-O(21) bond length is 2.84 Å. The Sr(1)-O(24) bond length is 2.89 Å. The Sr(1)-O(5) bond length is 2.69 Å. The Sr(1)-O(8) bond length is 2.68 Å. The Sr(1)-O(9) bond length is 2.76 Å. There is one shorter (2.76 Å) and one longer (2.92 Å) Sr(1)-O(1) bond length. In the second Sr site, Sr(2) is bonded to one O(10), one O(12), one O(13), one O(16), one O(18), one O(20), one O(21), one O(22), one O(5), one O(6), and two equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(2)O12 cuboctahedra, corners with three equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Sr(3)O12 cuboctahedra, corners with four equivalent Sr(4)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra, faces with two equivalent Sr(5)O12 cuboctahedra, faces with two equivalent Sr(8)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(2)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Mn(3)O6 octahedra. The Sr(2)-O(10) bond length is 3.03 Å. The Sr(2)-O(12) bond length is 2.75 Å. The Sr(2)-O(13) bond length is 2.68 Å. The Sr(2)-O(16) bond length is 2.68 Å. The Sr(2)-O(18) bond length is 2.92 Å. The Sr(2)-O(20) bond length is 2.76 Å. The Sr(2)-O(21) bond length is 2.89 Å. The Sr(2)-O(22) bond length is 2.85 Å. The Sr(2)-O(5) bond length is 3.01 Å. The Sr(2)-O(6) bond length is 3.00 Å. There is one shorter (2.77 Å) and one longer (2.93 Å) Sr(2)-O(2) bond length. In the third Sr site, Sr(3) is bonded to one O(11), one O(13), one O(14), one O(17), one O(19), one O(22), one O(23), one O(6), one O(7), one O(9), and two equivalent O(3) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(3)O12 cuboctahedra, corners with three equivalent Sr(2)O12 cuboctahedra, corners with three equivalent Sr(4)O12 cuboctahedra, corners with four equivalent Sr(1)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(5)O12 cuboctahedra, faces with two equivalent Sr(6)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(2)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Mn(4)O6 octahedra. The Sr(3)-O(11) bond length is 2.74 Å. The Sr(3)-O(13) bond length is 3.01 Å. The Sr(3)-O(14) bond length is 3.02 Å. The Sr(3)-O(17) bond length is 2.93 Å. The Sr(3)-O(19) bond length is 2.77 Å. The Sr(3)-O(22) bond length is 2.88 Å. The Sr(3)-O(23) bond length is 2.85 Å. The Sr(3)-O(6) bond length is 2.69 Å. The Sr(3)-O(7) bond length is 2.69 Å. The Sr(3)-O(9) bond length is 3.01 Å. There is one shorter (2.77 Å) and one longer (2.91 Å) Sr(3)-O(3) bond length. In the fourth Sr site, Sr(4) is bonded to one O(10), one O(12), one O(14), one O(15), one O(18), one O(20), one O(23), one O(24), one O(7), one O(8), and two equivalent O(4) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(4)O12 cuboctahedra, corners with three 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(5)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(6)O12 cuboctahedra, faces with two equivalent Sr(7)O12 cuboctahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(3)O6 octahedra, faces with two equivalent Nb(4)O6 octahedra, and faces with two equivalent Mn(2)O6 octahedra. The Sr(4)-O(10) bond length is 2.74 Å. The Sr(4)-O(12) bond length is 3.03 Å. The Sr(4)-O(14) bond length is 2.68 Å. The Sr(4)-O(15) bond length is 2.69 Å. The Sr(4)-O(18) bond length is 2.77 Å. The Sr(4)-O(20) bond length is 2.93 Å. The Sr(4)-O(23) bond length is 2.89 Å. The Sr(4)-O(24) bond length is 2.84 Å. The Sr(4)-O(7) bond length is 3.01 Å. The Sr(4)-O(8) bond length is 3.02 Å. There is one shorter (2.76 Å) and one longer (2.93 Å) Sr(4)-O(4) bond length. In the fifth Sr site, Sr(5) is bonded to one O(10), one O(17), one O(18), one O(2), one O(21), one O(23), one O(3), one O(5), one O(7), one O(9), and two equivalent O(13) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(5)O12 cuboctahedra, corners with three equivalent Sr(6)O12 cuboctahedra, corners with three equivalent Sr(8)O12 cuboctahedra, corners with four equivalent Sr(7)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Mn(3)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with two equivalent Mn(2)O6 octahedra. The Sr(5)-O(10) bond length is 2.88 Å. The Sr(5)-O(17) bond length is 2.99 Å. The Sr(5)-O(18) bond length is 3.03 Å. The Sr(5)-O(2) bond length is 2.68 Å. The Sr(5)-O(21) bond length is 3.02 Å. The Sr(5)-O(23) bond length is 2.75 Å. The Sr(5)-O(3) bond length is 2.69 Å. The Sr(5)-O(5) bond length is 2.92 Å. The Sr(5)-O(7) bond length is 2.77 Å. The Sr(5)-O(9) bond length is 2.85 Å. There is one shorter (2.77 Å) and one longer (2.92 Å) Sr(5)-O(13) bond length. In the sixth Sr site, Sr(6) is bonded to one O(10), one O(11), one O(18), one O(19), one O(22), one O(24), one O(3), one O(4), one O(6), one O(8), and two equivalent O(14) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(6)O12 cuboctahedra, corners with three equivalent Sr(5)O12 cuboctahedra, corners with three equivalent Sr(7)O12 cuboctahedra, corners with four equivalent Sr(8)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(2)O6 octahedra,  a faceface with one Mn(4)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Mn(1)O6 octahedra. The Sr(6)-O(10) bond length is 2.85 Å. The Sr(6)-O(11) bond length is 2.90 Å. The Sr(6)-O(18) bond length is 2.67 Å. The Sr(6)-O(19) bond length is 2.68 Å. The Sr(6)-O(22) bond length is 2.75 Å. The Sr(6)-O(24) bond length is 3.04 Å. The Sr(6)-O(3) bond length is 3.01 Å. The Sr(6)-O(4) bond length is 3.01 Å. The Sr(6)-O(6) bond length is 2.75 Å. The Sr(6)-O(8) bond length is 2.92 Å. There is one shorter (2.76 Å) and one longer (2.92 Å) Sr(6)-O(14) bond length. In the seventh Sr site, Sr(7) is bonded to one O(1), one O(11), one O(12), one O(19), one O(20), one O(21), one O(23), one O(4), one O(5), one O(7), and two equivalent O(15) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(7)O12 cuboctahedra, corners with three equivalent Sr(6)O12 cuboctahedra, corners with three equivalent Sr(8)O12 cuboctahedra, corners with four equivalent Sr(5)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(2)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Mn(3)O6 octahedra. The Sr(7)-O(1) bond length is 2.69 Å. The Sr(7)-O(11) bond length is 2.84 Å. The Sr(7)-O(12) bond length is 2.89 Å. The Sr(7)-O(19) bond length is 3.01 Å. The Sr(7)-O(20) bond length is 3.02 Å. The Sr(7)-O(21) bond length is 2.75 Å. The Sr(7)-O(23) bond length is 3.03 Å. The Sr(7)-O(4) bond length is 2.68 Å. The Sr(7)-O(5) bond length is 2.77 Å. The Sr(7)-O(7) bond length is 2.92 Å. There is one shorter (2.76 Å) and one longer (2.93 Å) Sr(7)-O(15) bond length. In the eighth Sr site, Sr(8) is bonded to one O(1), one O(12), one O(17), one O(2), one O(20), one O(22), one O(24), one O(6), one O(8), one O(9), and two equivalent O(16) atoms to form SrO12 cuboctahedra that share corners with two equivalent Sr(8)O12 cuboctahedra, corners with three equivalent Sr(5)O12 cuboctahedra, corners with three equivalent Sr(7)O12 cuboctahedra, corners with four equivalent Sr(6)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Mn(1)O6 octahedra,  a faceface with one Mn(3)O6 octahedra, faces with two equivalent Nb(4)O6 octahedra, and faces with two equivalent Mn(4)O6 octahedra. The Sr(8)-O(1) bond length is 3.01 Å. The Sr(8)-O(12) bond length is 2.84 Å. The Sr(8)-O(17) bond length is 2.69 Å. The Sr(8)-O(2) bond length is 3.02 Å. The Sr(8)-O(20) bond length is 2.68 Å. The Sr(8)-O(22) bond length is 3.02 Å. The Sr(8)-O(24) bond length is 2.74 Å. The Sr(8)-O(6) bond length is 2.94 Å. The Sr(8)-O(8) bond length is 2.77 Å. The Sr(8)-O(9) bond length is 2.88 Å. There is one shorter (2.77 Å) and one longer (2.92 Å) Sr(8)-O(16) bond length. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(13), one O(17), one O(21), one O(5), and one O(9) atom to form NbO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-8°. The Nb(1)-O(1) bond length is 2.07 Å. The Nb(1)-O(13) bond length is 1.94 Å. The Nb(1)-O(17) bond length is 1.94 Å. The Nb(1)-O(21) bond length is 2.01 Å. The Nb(1)-O(5) bond length is 2.07 Å. The Nb(1)-O(9) bond length is 2.01 Å. In the second Nb site, Nb(2) is bonded to one O(10), one O(14), one O(18), one O(2), one O(22), and one O(6) atom to form NbO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with two equivalent Sr(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-9°. The Nb(2)-O(10) bond length is 2.01 Å. The Nb(2)-O(14) bond length is 2.08 Å. The Nb(2)-O(18) bond length is 2.08 Å. The Nb(2)-O(2) bond length is 1.94 Å. The Nb(2)-O(22) bond length is 2.01 Å. The Nb(2)-O(6) bond length is 1.94 Å. In the third Nb site, Nb(3) is bonded to one O(11), one O(15), one O(19), one O(23), one O(3), and one O(7) atom to form NbO6 octahedra that share  a cornercorner with one Mn(3)O6 octahedra,  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 faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(7)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-8°. The Nb(3)-O(11) bond length is 2.01 Å. The Nb(3)-O(15) bond length is 1.94 Å. The Nb(3)-O(19) bond length is 1.94 Å. The Nb(3)-O(23) bond length is 2.01 Å. The Nb(3)-O(3) bond length is 2.07 Å. The Nb(3)-O(7) bond length is 2.07 Å. In the fourth Nb site, Nb(4) is bonded to one O(12), one O(16), one O(20), one O(24), one O(4), and one O(8) atom to form NbO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra, and faces with two equivalent Sr(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. The Nb(4)-O(12) bond length is 2.01 Å. The Nb(4)-O(16) bond length is 2.08 Å. The Nb(4)-O(20) bond length is 2.08 Å. The Nb(4)-O(24) bond length is 2.01 Å. The Nb(4)-O(4) bond length is 1.94 Å. The Nb(4)-O(8) bond length is 1.94 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(14), one O(19), one O(24), and one O(8) atom to form MnO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with two equivalent Sr(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. The Mn(1)-O(1) bond length is 1.94 Å. The Mn(1)-O(11) bond length is 1.96 Å. The Mn(1)-O(14) bond length is 1.94 Å. The Mn(1)-O(19) bond length is 2.20 Å. The Mn(1)-O(24) bond length is 1.96 Å. The Mn(1)-O(8) bond length is 2.20 Å. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(18), one O(23), one O(4), and one O(7) atom to form MnO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(3)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra,  a faceface with one Sr(7)O12 cuboctahedra, faces with two equivalent Sr(4)O12 cuboctahedra, and faces with two equivalent Sr(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. The Mn(2)-O(10) bond length is 1.96 Å. The Mn(2)-O(13) bond length is 2.20 Å. The Mn(2)-O(18) bond length is 1.94 Å. The Mn(2)-O(23) bond length is 1.96 Å. The Mn(2)-O(4) bond length is 2.20 Å. The Mn(2)-O(7) bond length is 1.94 Å. In the third Mn site, Mn(3) is bonded to one O(12), one O(15), one O(2), one O(20), one O(21), and one O(5) atom to form MnO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(4)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(8)O12 cuboctahedra, faces with two equivalent Sr(2)O12 cuboctahedra, and faces with two equivalent Sr(7)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. The Mn(3)-O(12) bond length is 1.96 Å. The Mn(3)-O(15) bond length is 2.20 Å. The Mn(3)-O(2) bond length is 2.20 Å. The Mn(3)-O(20) bond length is 1.94 Å. The Mn(3)-O(21) bond length is 1.96 Å. The Mn(3)-O(5) bond length is 1.94 Å. In the fourth Mn site, Mn(4) is bonded to one O(16), one O(17), one O(22), one O(3), one O(6), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra,  a faceface with one Sr(1)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra,  a faceface with one Sr(5)O12 cuboctahedra,  a faceface with one Sr(6)O12 cuboctahedra, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-9°. The Mn(4)-O(16) bond length is 1.94 Å. The Mn(4)-O(17) bond length is 2.19 Å. The Mn(4)-O(22) bond length is 1.96 Å. The Mn(4)-O(3) bond length is 1.94 Å. The Mn(4)-O(6) bond length is 2.20 Å. The Mn(4)-O(9) bond length is 1.97 Å. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Sr(7), one Sr(8), two equivalent Sr(1), one Nb(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Sr(5), one Sr(8), two equivalent Sr(2), one Nb(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Sr(5), one Sr(6), two equivalent Sr(3), one Nb(3), and one Mn(4) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(6), one Sr(7), two equivalent Sr(4), one Nb(4), and one Mn(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), one Sr(5), one Sr(7), one Nb(1), and one Mn(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(6), one Sr(8), one Nb(2), and one Mn(4) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Sr(3), one Sr(4), one Sr(5), one Sr(7), one Nb(3), and one Mn(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(4), one Sr(6), one Sr(8), one Nb(4), and one Mn(1) atom. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Sr(1), one Sr(3), one Sr(5), one Sr(8), one Nb(1), and one Mn(4) atom. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Sr(2), one Sr(4), one Sr(5), one Sr(6), one Nb(2), and one Mn(2) atom. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Sr(1), one Sr(3), one Sr(6), one Sr(7), one Nb(3), and one Mn(1) atom. In the twelfth O site, O(12) is bonded in a distorted linear geometry to one Sr(2), one Sr(4), one Sr(7), one Sr(8), one Nb(4), and one Mn(3) atom. In the thirteenth O site, O(13) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), two equivalent Sr(5), one Nb(1), and one Mn(2) atom. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to one Sr(3), one Sr(4), two equivalent Sr(6), one Nb(2), and one Mn(1) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(4), two equivalent Sr(7), one Nb(3), and one Mn(3) atom. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(8), one Nb(4), and one Mn(4) atom. In the seventeenth O site, O(17) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(3), one Sr(5), one Sr(8), one Nb(1), and one Mn(4) atom. In the eighteenth O site, O(18) is bonded in a 2-coordinate geometry to one Sr(2), one Sr(4), one Sr(5), one Sr(6), one Nb(2), and one Mn(2) atom. In the nineteenth O site, O(19) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(3), one Sr(6), one Sr(7), one Nb(3), and one Mn(1) atom. In the twentieth O site, O(20) is bonded in a 2-coordinate geometry to one Sr(2), one Sr(4), one Sr(7), one Sr(8), one Nb(4), and one Mn(3) atom. In the twenty-first O site, O(21) is bonded in a distorted linear geometry to one Sr(1), one Sr(2), one Sr(5), one Sr(7), one Nb(1), and one Mn(3) atom. In the twenty-second O site, O(22) is bonded in a distorted linear geometry to one Sr(2), one Sr(3), one Sr(6), one Sr(8), one Nb(2), and one Mn(4) atom. In the twenty-third O site, O(23) is bonded in a distorted linear geometry to one Sr(3), one Sr(4), one Sr(5), one Sr(7), one Nb(3), and one Mn(2) atom. In the twenty-fourth O site, O(24) is bonded in a distorted linear geometry to one Sr(1), one Sr(4), one Sr(6), one Sr(8), one Nb(4), and one Mn(1) atom.