The material structure described by Sr8MgMn6O20 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one O(11), one O(12), one O(14), one O(15), one O(2), one O(7), one O(8), and two equivalent O(18) atoms. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(16), one O(4), one O(7), one O(8), and two equivalent O(19) atoms. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one O(10), one O(13), one O(14), one O(20), one O(5), one O(6), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(1), one O(17), one O(19), one O(4), one O(9), and two equivalent O(13) atoms. In the fifth Sr site, Sr(5) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(13), one O(16), one O(4), one O(6), one O(9), and two equivalent O(17) atoms. In the sixth Sr site, Sr(6) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(20), one O(3), one O(6), and one O(9) atom. In the seventh Sr site, Sr(7) is bonded in a 9-coordinate geometry to one O(11), one O(12), one O(18), one O(2), one O(3), one O(7), one O(8), and two equivalent O(15) atoms. In the eighth Sr site, Sr(8) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(17), one O(19), one O(4), one O(7), one O(8), and two equivalent O(16) atoms. Mg(1) is bonded in a 5-coordinate geometry to one O(15), one O(2), one O(20), one O(3), and one O(5) atom. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(13), one O(17), one O(4), one O(6), and one O(9) atom to form a mixture of distorted face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 8-18°. In the second Mn site, Mn(2) is bonded to one O(10), one O(14), one O(2), one O(20), one O(3), and one O(5) atom to form distorted MnO6 octahedra that share  a cornercorner with one Mn(3)O5 square pyramid and  a faceface with one Mn(5)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(11), one O(15), one O(18), one O(2), and one O(8) atom to form a mixture of distorted face and corner-sharing MnO5 square pyramids. The corner-sharing octahedral tilt angles are 24°. In the fourth Mn site, Mn(4) is bonded to one O(1), one O(12), one O(16), one O(19), one O(4), and one O(7) atom to form a mixture of face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 8-18°. In the fifth Mn site, Mn(5) is bonded to one O(10), one O(17), one O(20), one O(5), one O(6), and one O(9) atom to form face-sharing MnO6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(11), one O(12), one O(15), one O(16), one O(7), and one O(8) atom to form MnO6 octahedra that share  a faceface with one Mn(4)O6 octahedra and  a faceface with one Mn(3)O5 square pyramid. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Sr(4), one Sr(5), one Sr(8), one Mn(1), and one Mn(4) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(7), one Mg(1), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(6), one Sr(7), one Mg(1), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Sr(2), one Sr(4), one Sr(5), one Sr(8), one Mn(1), and one Mn(4) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Mg(1), one Mn(2), and one Mn(5) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(5), one Sr(6), one Mn(1), and one Mn(5) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(4), and one Mn(6) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(3), and one Mn(6) atom. In the ninth O site, O(9) is bonded in a distorted octahedral geometry to one Sr(3), one Sr(4), one Sr(5), one Sr(6), one Mn(1), and one Mn(5) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(5), one Sr(6), one Mn(2), and one Mn(5) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(3), and one Mn(6) atom. In the twelfth O site, O(12) is bonded in a distorted octahedral geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(4), and one Mn(6) atom. In the thirteenth O site, O(13) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(5), two equivalent Sr(4), and one Mn(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Sr(6), and one Mn(2) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Sr(1), two equivalent Sr(7), one Mg(1), one Mn(3), and one Mn(6) atom. In the sixteenth O site, O(16) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(5), two equivalent Sr(8), one Mn(4), and one Mn(6) atom. In the seventeenth O site, O(17) is bonded in a 6-coordinate geometry to one Sr(4), one Sr(8), two equivalent Sr(5), one Mn(1), and one Mn(5) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Sr(7), two equivalent Sr(1), and one Mn(3) atom. In the nineteenth O site, O(19) is bonded in a 5-coordinate geometry to one Sr(4), one Sr(8), two equivalent Sr(2), and one Mn(4) atom. In the twentieth O site, O(20) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(6), one Mg(1), one Mn(2), and one Mn(5) atom. is represented by the CIF file [CIF]
data_Sr8MgMn6O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.758
_cell_length_b   7.050
_cell_length_c   13.623
_cell_angle_alpha   87.854
_cell_angle_beta   95.001
_cell_angle_gamma   117.597
_symmetry_Int_Tables_number   1
_cell_volume   488.212
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.308  0.451  0.112  1.0
  Sr  Sr1  1  0.763  0.513  0.894  1.0
  Sr  Sr2  1  0.682  0.505  0.457  1.0
  Sr  Sr3  1  0.209  0.510  0.658  1.0
  Sr  Sr4  1  0.900  0.934  0.649  1.0
  Sr  Sr5  1  0.970  0.208  0.401  1.0
  Sr  Sr6  1  0.600  0.048  0.122  1.0
  Sr  Sr7  1  0.469  0.929  0.864  1.0
  Mg  Mg8  1  0.144  0.951  0.288  1.0
  Mn  Mn9  1  0.561  0.241  0.660  1.0
  Mn  Mn10  1  0.445  0.766  0.343  1.0
  Mn  Mn11  1  0.938  0.706  0.134  1.0
  Mn  Mn12  1  0.117  0.247  0.850  1.0
  Mn  Mn13  1  0.427  0.981  0.500  1.0
  Mn  Mn14  1  0.036  0.986  0.995  1.0
  O  O15  1  0.294  0.208  0.744  1.0
  O  O16  1  0.249  0.756  0.221  1.0
  O  O17  1  0.774  0.892  0.285  1.0
  O  O18  1  0.832  0.241  0.766  1.0
  O  O19  1  0.147  0.739  0.424  1.0
  O  O20  1  0.266  0.157  0.525  1.0
  O  O21  1  0.362  0.208  0.955  1.0
  O  O22  1  0.168  0.781  0.009  1.0
  O  O23  1  0.772  0.225  0.552  1.0
  O  O24  1  0.622  0.825  0.475  1.0
  O  O25  1  0.702  0.759  0.039  1.0
  O  O26  1  0.918  0.207  0.971  1.0
  O  O27  1  0.701  0.541  0.646  1.0
  O  O28  1  0.353  0.482  0.330  1.0
  O  O29  1  0.125  0.048  0.138  1.0
  O  O30  1  0.928  0.920  0.858  1.0
  O  O31  1  0.397  0.906  0.641  1.0
  O  O32  1  0.740  0.420  0.144  1.0
  O  O33  1  0.302  0.545  0.840  1.0
  O  O34  1  0.493  0.089  0.365  1.0
[/CIF]
.
The material structure described by Sr8MgMn6O20 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one O(11), one O(12), one O(14), one O(15), one O(2), one O(7), one O(8), and two equivalent O(18) atoms. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(16), one O(4), one O(7), one O(8), and two equivalent O(19) atoms. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one O(10), one O(13), one O(14), one O(20), one O(5), one O(6), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(1), one O(17), one O(19), one O(4), one O(9), and two equivalent O(13) atoms. In the fifth Sr site, Sr(5) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(13), one O(16), one O(4), one O(6), one O(9), and two equivalent O(17) atoms. In the sixth Sr site, Sr(6) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(20), one O(3), one O(6), and one O(9) atom. In the seventh Sr site, Sr(7) is bonded in a 9-coordinate geometry to one O(11), one O(12), one O(18), one O(2), one O(3), one O(7), one O(8), and two equivalent O(15) atoms. In the eighth Sr site, Sr(8) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(17), one O(19), one O(4), one O(7), one O(8), and two equivalent O(16) atoms. Mg(1) is bonded in a 5-coordinate geometry to one O(15), one O(2), one O(20), one O(3), and one O(5) atom. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(13), one O(17), one O(4), one O(6), and one O(9) atom to form a mixture of distorted face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 8-18°. In the second Mn site, Mn(2) is bonded to one O(10), one O(14), one O(2), one O(20), one O(3), and one O(5) atom to form distorted MnO6 octahedra that share  a cornercorner with one Mn(3)O5 square pyramid and  a faceface with one Mn(5)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(11), one O(15), one O(18), one O(2), and one O(8) atom to form a mixture of distorted face and corner-sharing MnO5 square pyramids. The corner-sharing octahedral tilt angles are 24°. In the fourth Mn site, Mn(4) is bonded to one O(1), one O(12), one O(16), one O(19), one O(4), and one O(7) atom to form a mixture of face and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 8-18°. In the fifth Mn site, Mn(5) is bonded to one O(10), one O(17), one O(20), one O(5), one O(6), and one O(9) atom to form face-sharing MnO6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(11), one O(12), one O(15), one O(16), one O(7), and one O(8) atom to form MnO6 octahedra that share  a faceface with one Mn(4)O6 octahedra and  a faceface with one Mn(3)O5 square pyramid. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Sr(4), one Sr(5), one Sr(8), one Mn(1), and one Mn(4) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(7), one Mg(1), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(6), one Sr(7), one Mg(1), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Sr(2), one Sr(4), one Sr(5), one Sr(8), one Mn(1), and one Mn(4) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Mg(1), one Mn(2), and one Mn(5) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(5), one Sr(6), one Mn(1), and one Mn(5) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(4), and one Mn(6) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(3), and one Mn(6) atom. In the ninth O site, O(9) is bonded in a distorted octahedral geometry to one Sr(3), one Sr(4), one Sr(5), one Sr(6), one Mn(1), and one Mn(5) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(5), one Sr(6), one Mn(2), and one Mn(5) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(3), and one Mn(6) atom. In the twelfth O site, O(12) is bonded in a distorted octahedral geometry to one Sr(1), one Sr(2), one Sr(7), one Sr(8), one Mn(4), and one Mn(6) atom. In the thirteenth O site, O(13) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(5), two equivalent Sr(4), and one Mn(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Sr(6), and one Mn(2) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Sr(1), two equivalent Sr(7), one Mg(1), one Mn(3), and one Mn(6) atom. In the sixteenth O site, O(16) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(5), two equivalent Sr(8), one Mn(4), and one Mn(6) atom. In the seventeenth O site, O(17) is bonded in a 6-coordinate geometry to one Sr(4), one Sr(8), two equivalent Sr(5), one Mn(1), and one Mn(5) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Sr(7), two equivalent Sr(1), and one Mn(3) atom. In the nineteenth O site, O(19) is bonded in a 5-coordinate geometry to one Sr(4), one Sr(8), two equivalent Sr(2), and one Mn(4) atom. In the twentieth O site, O(20) is bonded in a 5-coordinate geometry to one Sr(3), one Sr(6), one Mg(1), one Mn(2), and one Mn(5) atom. is represented by the CIF file [CIF]
data_Sr8MgMn6O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.758
_cell_length_b   7.050
_cell_length_c   13.623
_cell_angle_alpha   87.854
_cell_angle_beta   95.001
_cell_angle_gamma   117.597
_symmetry_Int_Tables_number   1
_cell_volume   488.212
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.308  0.451  0.112  1.0
  Sr  Sr1  1  0.763  0.513  0.894  1.0
  Sr  Sr2  1  0.682  0.505  0.457  1.0
  Sr  Sr3  1  0.209  0.510  0.658  1.0
  Sr  Sr4  1  0.900  0.934  0.649  1.0
  Sr  Sr5  1  0.970  0.208  0.401  1.0
  Sr  Sr6  1  0.600  0.048  0.122  1.0
  Sr  Sr7  1  0.469  0.929  0.864  1.0
  Mg  Mg8  1  0.144  0.951  0.288  1.0
  Mn  Mn9  1  0.561  0.241  0.660  1.0
  Mn  Mn10  1  0.445  0.766  0.343  1.0
  Mn  Mn11  1  0.938  0.706  0.134  1.0
  Mn  Mn12  1  0.117  0.247  0.850  1.0
  Mn  Mn13  1  0.427  0.981  0.500  1.0
  Mn  Mn14  1  0.036  0.986  0.995  1.0
  O  O15  1  0.294  0.208  0.744  1.0
  O  O16  1  0.249  0.756  0.221  1.0
  O  O17  1  0.774  0.892  0.285  1.0
  O  O18  1  0.832  0.241  0.766  1.0
  O  O19  1  0.147  0.739  0.424  1.0
  O  O20  1  0.266  0.157  0.525  1.0
  O  O21  1  0.362  0.208  0.955  1.0
  O  O22  1  0.168  0.781  0.009  1.0
  O  O23  1  0.772  0.225  0.552  1.0
  O  O24  1  0.622  0.825  0.475  1.0
  O  O25  1  0.702  0.759  0.039  1.0
  O  O26  1  0.918  0.207  0.971  1.0
  O  O27  1  0.701  0.541  0.646  1.0
  O  O28  1  0.353  0.482  0.330  1.0
  O  O29  1  0.125  0.048  0.138  1.0
  O  O30  1  0.928  0.920  0.858  1.0
  O  O31  1  0.397  0.906  0.641  1.0
  O  O32  1  0.740  0.420  0.144  1.0
  O  O33  1  0.302  0.545  0.840  1.0
  O  O34  1  0.493  0.089  0.365  1.0
[/CIF]
.