The crystal structure described by Ba8Mn8O21 crystallizes in the monoclinic Pm space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted q6 geometry to one O(1), one O(10), one O(13), one O(15), one O(2), one O(4), one O(5), one O(6), one O(8), and two equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(11), one O(15), one O(7), two equivalent O(1), two equivalent O(3), two equivalent O(5), and two equivalent O(8) atoms. In the third Ba site, Ba(3) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(13), one O(14), one O(5), one O(6), one O(7), and two equivalent O(9) atoms. In the fourth Ba site, Ba(4) is bonded in a 9-coordinate geometry to one O(12), one O(2), one O(4), two equivalent O(1), two equivalent O(5), and two equivalent O(9) atoms. In the fifth Ba site, Ba(5) is bonded in a distorted q6 geometry to one O(11), one O(15), one O(7), two equivalent O(13), two equivalent O(14), two equivalent O(6), and two equivalent O(9) atoms. In the sixth Ba site, Ba(6) is bonded in a 11-coordinate geometry to one O(12), one O(2), one O(4), two equivalent O(10), two equivalent O(13), two equivalent O(3), and two equivalent O(6) atoms. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form MnO5 square pyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O5 square pyramid, and  an edgeedge with one Mn(1)O5 square pyramid. The corner-sharing octahedral tilt angles are 5°. In the second Mn site, Mn(2) is bonded to one O(1), one O(11), one O(5), one O(7), one O(8), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Mn(3)O5 square pyramid, corners with two equivalent Mn(1)O5 square pyramids, and  a faceface with one Mn(2)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(10), one O(12), one O(13), one O(6), and one O(9) atom to form MnO5 square pyramids that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(4)O5 square pyramids, and  an edgeedge with one Mn(3)O5 square pyramid. The corner-sharing octahedral tilt angles are 6°. In the fourth Mn site, Mn(4) is bonded to one O(13), one O(14), one O(15), one O(3), and one O(6) atom to form a mixture of corner and edge-sharing MnO5 square pyramids. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(1), and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to one Ba(2), one Ba(6), two equivalent Ba(1), one Mn(1), and one Mn(4) atom. In the fourth O site, O(4) is bonded in a distorted L-shaped geometry to one Ba(4), one Ba(6), two equivalent Ba(1), and two equivalent Mn(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), one Ba(5), one Ba(6), one Mn(3), and one Mn(4) atom. In the seventh O site, O(7) is bonded in a distorted L-shaped geometry to one Ba(2), one Ba(5), two equivalent Ba(3), and two equivalent Mn(2) atoms. In the eighth O site, O(8) is bonded in a distorted L-shaped geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Mn(2) atoms. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Ba(4), one Ba(5), two equivalent Ba(3), one Mn(2), and one Mn(3) atom. In the tenth O site, O(10) is bonded in a distorted L-shaped geometry to two equivalent Ba(1), two equivalent Ba(6), and two equivalent Mn(3) atoms. In the eleventh O site, O(11) is bonded in a distorted L-shaped geometry to one Ba(2), one Ba(5), two equivalent Ba(3), and two equivalent Mn(2) atoms. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(3), and two equivalent Mn(3) atoms. In the thirteenth O site, O(13) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), one Ba(5), one Ba(6), one Mn(3), and one Mn(4) atom. In the fourteenth O site, O(14) is bonded to two equivalent Ba(3), two equivalent Ba(5), and two equivalent Mn(4) atoms to form distorted corner-sharing OBa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 9°. In the fifteenth O site, O(15) is bonded in a distorted L-shaped geometry to one Ba(2), one Ba(5), two equivalent Ba(1), and two equivalent Mn(4) atoms. is represented by the CIF card [CIF]
data_Ba8Mn8O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.427
_cell_length_b   5.706
_cell_length_c   9.914
_cell_angle_alpha   89.609
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   533.240
_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
  Ba  Ba0  1  0.763  0.992  0.999  1.0
  Ba  Ba1  1  0.500  0.509  0.166  1.0
  Ba  Ba2  1  0.280  0.493  0.505  1.0
  Ba  Ba3  1  0.000  0.004  0.334  1.0
  Ba  Ba4  1  0.500  0.993  0.666  1.0
  Ba  Ba5  1  0.237  0.992  0.999  1.0
  Ba  Ba6  1  0.720  0.493  0.505  1.0
  Ba  Ba7  1  0.000  0.492  0.835  1.0
  Mn  Mn8  1  0.146  0.497  0.166  1.0
  Mn  Mn9  1  0.854  0.497  0.166  1.0
  Mn  Mn10  1  0.637  0.998  0.332  1.0
  Mn  Mn11  1  0.143  0.017  0.664  1.0
  Mn  Mn12  1  0.363  0.998  0.332  1.0
  Mn  Mn13  1  0.857  0.017  0.664  1.0
  Mn  Mn14  1  0.642  0.515  0.830  1.0
  Mn  Mn15  1  0.358  0.515  0.830  1.0
  O  O16  1  0.249  0.248  0.256  1.0
  O  O17  1  0.000  0.279  0.117  1.0
  O  O18  1  0.743  0.492  0.995  1.0
  O  O19  1  0.000  0.713  0.115  1.0
  O  O20  1  0.752  0.747  0.257  1.0
  O  O21  1  0.238  0.757  0.737  1.0
  O  O22  1  0.762  0.757  0.737  1.0
  O  O23  1  0.248  0.747  0.257  1.0
  O  O24  1  0.500  0.779  0.404  1.0
  O  O25  1  0.500  0.003  0.187  1.0
  O  O26  1  0.750  0.993  0.494  1.0
  O  O27  1  0.250  0.993  0.494  1.0
  O  O28  1  0.000  0.984  0.803  1.0
  O  O29  1  0.500  0.213  0.406  1.0
  O  O30  1  0.000  0.229  0.582  1.0
  O  O31  1  0.751  0.248  0.256  1.0
  O  O32  1  0.738  0.255  0.760  1.0
  O  O33  1  0.262  0.255  0.760  1.0
  O  O34  1  0.500  0.489  0.689  1.0
  O  O35  1  0.257  0.492  0.995  1.0
  O  O36  1  0.500  0.723  0.909  1.0
[/CIF]
.
The crystal structure described by Ba8Mn8O21 crystallizes in the monoclinic Pm space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted q6 geometry to one O(1), one O(10), one O(13), one O(15), one O(2), one O(4), one O(5), one O(6), one O(8), and two equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(11), one O(15), one O(7), two equivalent O(1), two equivalent O(3), two equivalent O(5), and two equivalent O(8) atoms. In the third Ba site, Ba(3) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(13), one O(14), one O(5), one O(6), one O(7), and two equivalent O(9) atoms. In the fourth Ba site, Ba(4) is bonded in a 9-coordinate geometry to one O(12), one O(2), one O(4), two equivalent O(1), two equivalent O(5), and two equivalent O(9) atoms. In the fifth Ba site, Ba(5) is bonded in a distorted q6 geometry to one O(11), one O(15), one O(7), two equivalent O(13), two equivalent O(14), two equivalent O(6), and two equivalent O(9) atoms. In the sixth Ba site, Ba(6) is bonded in a 11-coordinate geometry to one O(12), one O(2), one O(4), two equivalent O(10), two equivalent O(13), two equivalent O(3), and two equivalent O(6) atoms. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form MnO5 square pyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O5 square pyramid, and  an edgeedge with one Mn(1)O5 square pyramid. The corner-sharing octahedral tilt angles are 5°. In the second Mn site, Mn(2) is bonded to one O(1), one O(11), one O(5), one O(7), one O(8), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Mn(3)O5 square pyramid, corners with two equivalent Mn(1)O5 square pyramids, and  a faceface with one Mn(2)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(10), one O(12), one O(13), one O(6), and one O(9) atom to form MnO5 square pyramids that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(4)O5 square pyramids, and  an edgeedge with one Mn(3)O5 square pyramid. The corner-sharing octahedral tilt angles are 6°. In the fourth Mn site, Mn(4) is bonded to one O(13), one O(14), one O(15), one O(3), and one O(6) atom to form a mixture of corner and edge-sharing MnO5 square pyramids. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(1), and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to one Ba(2), one Ba(6), two equivalent Ba(1), one Mn(1), and one Mn(4) atom. In the fourth O site, O(4) is bonded in a distorted L-shaped geometry to one Ba(4), one Ba(6), two equivalent Ba(1), and two equivalent Mn(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), one Ba(5), one Ba(6), one Mn(3), and one Mn(4) atom. In the seventh O site, O(7) is bonded in a distorted L-shaped geometry to one Ba(2), one Ba(5), two equivalent Ba(3), and two equivalent Mn(2) atoms. In the eighth O site, O(8) is bonded in a distorted L-shaped geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Mn(2) atoms. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Ba(4), one Ba(5), two equivalent Ba(3), one Mn(2), and one Mn(3) atom. In the tenth O site, O(10) is bonded in a distorted L-shaped geometry to two equivalent Ba(1), two equivalent Ba(6), and two equivalent Mn(3) atoms. In the eleventh O site, O(11) is bonded in a distorted L-shaped geometry to one Ba(2), one Ba(5), two equivalent Ba(3), and two equivalent Mn(2) atoms. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(3), and two equivalent Mn(3) atoms. In the thirteenth O site, O(13) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), one Ba(5), one Ba(6), one Mn(3), and one Mn(4) atom. In the fourteenth O site, O(14) is bonded to two equivalent Ba(3), two equivalent Ba(5), and two equivalent Mn(4) atoms to form distorted corner-sharing OBa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 9°. In the fifteenth O site, O(15) is bonded in a distorted L-shaped geometry to one Ba(2), one Ba(5), two equivalent Ba(1), and two equivalent Mn(4) atoms. is represented by the CIF card [CIF]
data_Ba8Mn8O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.427
_cell_length_b   5.706
_cell_length_c   9.914
_cell_angle_alpha   89.609
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   533.240
_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
  Ba  Ba0  1  0.763  0.992  0.999  1.0
  Ba  Ba1  1  0.500  0.509  0.166  1.0
  Ba  Ba2  1  0.280  0.493  0.505  1.0
  Ba  Ba3  1  0.000  0.004  0.334  1.0
  Ba  Ba4  1  0.500  0.993  0.666  1.0
  Ba  Ba5  1  0.237  0.992  0.999  1.0
  Ba  Ba6  1  0.720  0.493  0.505  1.0
  Ba  Ba7  1  0.000  0.492  0.835  1.0
  Mn  Mn8  1  0.146  0.497  0.166  1.0
  Mn  Mn9  1  0.854  0.497  0.166  1.0
  Mn  Mn10  1  0.637  0.998  0.332  1.0
  Mn  Mn11  1  0.143  0.017  0.664  1.0
  Mn  Mn12  1  0.363  0.998  0.332  1.0
  Mn  Mn13  1  0.857  0.017  0.664  1.0
  Mn  Mn14  1  0.642  0.515  0.830  1.0
  Mn  Mn15  1  0.358  0.515  0.830  1.0
  O  O16  1  0.249  0.248  0.256  1.0
  O  O17  1  0.000  0.279  0.117  1.0
  O  O18  1  0.743  0.492  0.995  1.0
  O  O19  1  0.000  0.713  0.115  1.0
  O  O20  1  0.752  0.747  0.257  1.0
  O  O21  1  0.238  0.757  0.737  1.0
  O  O22  1  0.762  0.757  0.737  1.0
  O  O23  1  0.248  0.747  0.257  1.0
  O  O24  1  0.500  0.779  0.404  1.0
  O  O25  1  0.500  0.003  0.187  1.0
  O  O26  1  0.750  0.993  0.494  1.0
  O  O27  1  0.250  0.993  0.494  1.0
  O  O28  1  0.000  0.984  0.803  1.0
  O  O29  1  0.500  0.213  0.406  1.0
  O  O30  1  0.000  0.229  0.582  1.0
  O  O31  1  0.751  0.248  0.256  1.0
  O  O32  1  0.738  0.255  0.760  1.0
  O  O33  1  0.262  0.255  0.760  1.0
  O  O34  1  0.500  0.489  0.689  1.0
  O  O35  1  0.257  0.492  0.995  1.0
  O  O36  1  0.500  0.723  0.909  1.0
[/CIF]
.