The material described by Ca8CrMn7O21 crystallizes in the monoclinic Pm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted q6 geometry to one O(10), one O(14), one O(15), one O(16), one O(17), one O(2), one O(7), one O(8), and one O(9) atom. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(10), one O(15), one O(17), one O(3), one O(5), one O(6), and one O(8) atom. In the third Ca site, Ca(3) is bonded in a 9-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(15), one O(16), one O(17), one O(2), and one O(4) atom. In the fourth Ca site, Ca(4) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(13), one O(14), one O(15), one O(16), one O(17), one O(3), one O(5), and one O(6) atom. Cr(1) is bonded to one O(1), one O(7), and two equivalent O(14) atoms to form CrO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(1)O5 square pyramid, and  a cornercorner with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 39°. There are seven inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(8), and two equivalent O(15) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, and  a cornercorner with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the second Mn site, Mn(2) is bonded to one O(12), one O(2), one O(3), one O(9), and two equivalent O(14) atoms to form distorted MnO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(6)O5 square pyramids, and corners with two equivalent Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the third Mn site, Mn(3) is bonded to one O(10), one O(13), one O(2), one O(3), and two equivalent O(15) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(1)O5 square pyramids, and corners with two equivalent Mn(7)O5 square pyramids. The corner-sharing octahedral tilt angles range from 3-8°. In the fourth Mn site, Mn(4) is bonded to one O(4), one O(5), one O(7), and two equivalent O(16) atoms to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O5 square pyramids, and  a cornercorner with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-29°. In the fifth Mn site, Mn(5) is bonded to one O(11), one O(4), one O(5), one O(8), and two equivalent O(17) atoms to form corner-sharing MnO6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(12), one O(6), one O(9), and two equivalent O(16) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(7)O5 square pyramid, and corners with two equivalent Mn(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 13-19°. In the seventh Mn site, Mn(7) is bonded to one O(10), one O(13), one O(6), and two equivalent O(17) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, and  a cornercorner with one Mn(6)O5 square pyramid. The corner-sharing octahedral tilt angles range from 4-9°. There are seventeen inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(4), one Cr(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Ca(1), two equivalent Ca(3), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Ca(2), two equivalent Ca(4), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Ca(3), one Mn(4), and one Mn(5) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), one Mn(4), and one Mn(5) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), one Mn(6), and one Mn(7) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one Cr(1), and one Mn(4) atom. In the eighth O site, O(8) is bonded to two equivalent Ca(1), two equivalent Ca(2), one Mn(1), and one Mn(5) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Mn(2), and one Mn(6) atom. In the tenth O site, O(10) is bonded to two equivalent Ca(1), two equivalent Ca(2), one Mn(3), and one Mn(7) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 4°. In the eleventh O site, O(11) is bonded to two equivalent Ca(3), two equivalent Ca(4), one Mn(1), and one Mn(5) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent Ca(3), one Mn(2), and one Mn(6) atom. In the thirteenth O site, O(13) is bonded to two equivalent Ca(3), two equivalent Ca(4), one Mn(3), and one Mn(7) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 4°. In the fourteenth O site, O(14) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(3), one Ca(4), one Cr(1), and one Mn(2) atom. In the fifteenth O site, O(15) is bonded to one Ca(1), one Ca(2), one Ca(3), one Ca(4), one Mn(1), and one Mn(3) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one Ca(1), one Ca(3), one Ca(4), one Mn(4), and one Mn(6) atom. In the seventeenth O site, O(17) is bonded to one Ca(1), one Ca(2), one Ca(3), one Ca(4), one Mn(5), and one Mn(7) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca8Mn7CrO21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.779
_cell_length_b   7.749
_cell_length_c   7.686
_cell_angle_alpha   90.000
_cell_angle_beta   90.091
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   463.343
_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
  Ca  Ca0  1  0.235  0.263  0.245  1.0
  Ca  Ca1  1  0.269  0.267  0.701  1.0
  Ca  Ca2  1  0.235  0.737  0.245  1.0
  Ca  Ca3  1  0.269  0.733  0.701  1.0
  Ca  Ca4  1  0.739  0.258  0.260  1.0
  Ca  Ca5  1  0.755  0.246  0.724  1.0
  Ca  Ca6  1  0.739  0.742  0.260  1.0
  Ca  Ca7  1  0.755  0.754  0.724  1.0
  Mn  Mn8  1  0.007  0.000  0.503  1.0
  Mn  Mn9  1  0.991  0.500  0.009  1.0
  Mn  Mn10  1  0.002  0.500  0.498  1.0
  Mn  Mn11  1  0.495  0.000  0.998  1.0
  Mn  Mn12  1  0.510  0.000  0.481  1.0
  Mn  Mn13  1  0.499  0.500  0.992  1.0
  Mn  Mn14  1  0.505  0.500  0.498  1.0
  Cr  Cr15  1  0.015  0.000  0.990  1.0
  O  O16  1  0.960  0.000  0.765  1.0
  O  O17  1  0.013  0.500  0.255  1.0
  O  O18  1  0.004  0.500  0.757  1.0
  O  O19  1  0.564  0.000  0.232  1.0
  O  O20  1  0.527  0.000  0.747  1.0
  O  O21  1  0.493  0.500  0.746  1.0
  O  O22  1  0.237  0.000  0.048  1.0
  O  O23  1  0.256  0.000  0.483  1.0
  O  O24  1  0.252  0.500  0.030  1.0
  O  O25  1  0.259  0.500  0.487  1.0
  O  O26  1  0.762  0.000  0.484  1.0
  O  O27  1  0.738  0.500  0.042  1.0
  O  O28  1  0.749  0.500  0.489  1.0
  O  O29  1  0.946  0.207  0.062  1.0
  O  O30  1  0.012  0.248  0.499  1.0
  O  O31  1  0.946  0.793  0.062  1.0
  O  O32  1  0.012  0.752  0.499  1.0
  O  O33  1  0.501  0.254  0.018  1.0
  O  O34  1  0.499  0.255  0.473  1.0
  O  O35  1  0.501  0.746  0.018  1.0
  O  O36  1  0.499  0.745  0.473  1.0
[/CIF]
.
The material described by Ca8CrMn7O21 crystallizes in the monoclinic Pm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted q6 geometry to one O(10), one O(14), one O(15), one O(16), one O(17), one O(2), one O(7), one O(8), and one O(9) atom. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(10), one O(15), one O(17), one O(3), one O(5), one O(6), and one O(8) atom. In the third Ca site, Ca(3) is bonded in a 9-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(15), one O(16), one O(17), one O(2), and one O(4) atom. In the fourth Ca site, Ca(4) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(13), one O(14), one O(15), one O(16), one O(17), one O(3), one O(5), and one O(6) atom. Cr(1) is bonded to one O(1), one O(7), and two equivalent O(14) atoms to form CrO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(1)O5 square pyramid, and  a cornercorner with one Mn(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 39°. There are seven inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(8), and two equivalent O(15) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, and  a cornercorner with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the second Mn site, Mn(2) is bonded to one O(12), one O(2), one O(3), one O(9), and two equivalent O(14) atoms to form distorted MnO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(6)O5 square pyramids, and corners with two equivalent Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the third Mn site, Mn(3) is bonded to one O(10), one O(13), one O(2), one O(3), and two equivalent O(15) atoms to form MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(1)O5 square pyramids, and corners with two equivalent Mn(7)O5 square pyramids. The corner-sharing octahedral tilt angles range from 3-8°. In the fourth Mn site, Mn(4) is bonded to one O(4), one O(5), one O(7), and two equivalent O(16) atoms to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O5 square pyramids, and  a cornercorner with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-29°. In the fifth Mn site, Mn(5) is bonded to one O(11), one O(4), one O(5), one O(8), and two equivalent O(17) atoms to form corner-sharing MnO6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(12), one O(6), one O(9), and two equivalent O(16) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(7)O5 square pyramid, and corners with two equivalent Mn(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 13-19°. In the seventh Mn site, Mn(7) is bonded to one O(10), one O(13), one O(6), and two equivalent O(17) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, and  a cornercorner with one Mn(6)O5 square pyramid. The corner-sharing octahedral tilt angles range from 4-9°. There are seventeen inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(4), one Cr(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Ca(1), two equivalent Ca(3), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Ca(2), two equivalent Ca(4), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Ca(3), one Mn(4), and one Mn(5) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), one Mn(4), and one Mn(5) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to two equivalent Ca(2), two equivalent Ca(4), one Mn(6), and one Mn(7) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one Cr(1), and one Mn(4) atom. In the eighth O site, O(8) is bonded to two equivalent Ca(1), two equivalent Ca(2), one Mn(1), and one Mn(5) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Mn(2), and one Mn(6) atom. In the tenth O site, O(10) is bonded to two equivalent Ca(1), two equivalent Ca(2), one Mn(3), and one Mn(7) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 4°. In the eleventh O site, O(11) is bonded to two equivalent Ca(3), two equivalent Ca(4), one Mn(1), and one Mn(5) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent Ca(3), one Mn(2), and one Mn(6) atom. In the thirteenth O site, O(13) is bonded to two equivalent Ca(3), two equivalent Ca(4), one Mn(3), and one Mn(7) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 4°. In the fourteenth O site, O(14) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(3), one Ca(4), one Cr(1), and one Mn(2) atom. In the fifteenth O site, O(15) is bonded to one Ca(1), one Ca(2), one Ca(3), one Ca(4), one Mn(1), and one Mn(3) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one Ca(1), one Ca(3), one Ca(4), one Mn(4), and one Mn(6) atom. In the seventeenth O site, O(17) is bonded to one Ca(1), one Ca(2), one Ca(3), one Ca(4), one Mn(5), and one Mn(7) atom to form a mixture of distorted edge, corner, and face-sharing OCa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca8Mn7CrO21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.779
_cell_length_b   7.749
_cell_length_c   7.686
_cell_angle_alpha   90.000
_cell_angle_beta   90.091
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   463.343
_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
  Ca  Ca0  1  0.235  0.263  0.245  1.0
  Ca  Ca1  1  0.269  0.267  0.701  1.0
  Ca  Ca2  1  0.235  0.737  0.245  1.0
  Ca  Ca3  1  0.269  0.733  0.701  1.0
  Ca  Ca4  1  0.739  0.258  0.260  1.0
  Ca  Ca5  1  0.755  0.246  0.724  1.0
  Ca  Ca6  1  0.739  0.742  0.260  1.0
  Ca  Ca7  1  0.755  0.754  0.724  1.0
  Mn  Mn8  1  0.007  0.000  0.503  1.0
  Mn  Mn9  1  0.991  0.500  0.009  1.0
  Mn  Mn10  1  0.002  0.500  0.498  1.0
  Mn  Mn11  1  0.495  0.000  0.998  1.0
  Mn  Mn12  1  0.510  0.000  0.481  1.0
  Mn  Mn13  1  0.499  0.500  0.992  1.0
  Mn  Mn14  1  0.505  0.500  0.498  1.0
  Cr  Cr15  1  0.015  0.000  0.990  1.0
  O  O16  1  0.960  0.000  0.765  1.0
  O  O17  1  0.013  0.500  0.255  1.0
  O  O18  1  0.004  0.500  0.757  1.0
  O  O19  1  0.564  0.000  0.232  1.0
  O  O20  1  0.527  0.000  0.747  1.0
  O  O21  1  0.493  0.500  0.746  1.0
  O  O22  1  0.237  0.000  0.048  1.0
  O  O23  1  0.256  0.000  0.483  1.0
  O  O24  1  0.252  0.500  0.030  1.0
  O  O25  1  0.259  0.500  0.487  1.0
  O  O26  1  0.762  0.000  0.484  1.0
  O  O27  1  0.738  0.500  0.042  1.0
  O  O28  1  0.749  0.500  0.489  1.0
  O  O29  1  0.946  0.207  0.062  1.0
  O  O30  1  0.012  0.248  0.499  1.0
  O  O31  1  0.946  0.793  0.062  1.0
  O  O32  1  0.012  0.752  0.499  1.0
  O  O33  1  0.501  0.254  0.018  1.0
  O  O34  1  0.499  0.255  0.473  1.0
  O  O35  1  0.501  0.746  0.018  1.0
  O  O36  1  0.499  0.745  0.473  1.0
[/CIF]
.