The crystal structure described by SrCa7Cr2Mn6O20 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P1 space group. Sr(1) is bonded in a 10-coordinate geometry to one O(10), one O(14), one O(15), one O(17), one O(18), one O(2), one O(4), one O(7), one O(8), and one O(9) atom. There are seven inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 9-coordinate geometry to one O(10), one O(15), one O(17), one O(18), one O(3), one O(5), one O(6), one O(8), and one O(9) atom. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(10), one O(16), one O(19), one O(2), one O(20), one O(7), one O(8), and one O(9) atom. In the third Ca site, Ca(3) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(16), one O(20), one O(3), one O(5), one O(6), one O(8), and one O(9) atom. In the fourth Ca site, Ca(4) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(15), one O(17), one O(18), and one O(4) atom. In the fifth Ca site, Ca(5) is bonded in a 8-coordinate geometry to one O(11), one O(13), one O(15), one O(17), one O(18), one O(3), one O(5), and one O(6) atom. In the sixth Ca site, Ca(6) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(13), one O(16), one O(19), one O(2), one O(20), and one O(4) atom. In the seventh Ca site, Ca(7) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(13), one O(16), one O(19), one O(20), one O(3), one O(5), and one O(6) atom. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a trigonal planar geometry to one O(1), one O(14), and one O(7) atom. In the second Cr site, Cr(2) is bonded to one O(17), one O(19), one O(4), one O(5), and one O(7) atom to form CrO5 trigonal bipyramids that share corners with two equivalent Mn(4)O6 octahedra and corners with two equivalent Mn(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 16-26°. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(15), one O(16), and one O(8) atom to form corner-sharing MnO5 square pyramids. The corner-sharing octahedral tilt angles range from 3-18°. In the second Mn site, Mn(2) is bonded to one O(12), one O(14), one O(2), one O(3), and one O(9) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(3)O6 octahedra and corners with two equivalent Mn(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 11-18°. In the third Mn site, Mn(3) is bonded to one O(10), one O(13), one O(15), one O(16), one O(2), and one O(3) atom to form corner-sharing MnO6 octahedra. In the fourth Mn site, Mn(4) is bonded to one O(11), one O(18), one O(20), one O(4), one O(5), and one O(8) atom to form MnO6 octahedra that share corners with two equivalent Mn(1)O5 square pyramids, corners with two equivalent Mn(6)O5 square pyramids, and corners with two equivalent Cr(2)O5 trigonal bipyramids. In the fifth Mn site, Mn(5) is bonded to one O(12), one O(17), one O(19), one O(6), and one O(9) atom to form MnO5 square pyramids that share  a cornercorner with one Mn(6)O5 square pyramid, corners with two equivalent Cr(2)O5 trigonal bipyramids, and corners with two equivalent Mn(2)O5 trigonal bipyramids. In the sixth Mn site, Mn(6) is bonded to one O(10), one O(13), one O(18), one O(20), and one O(6) atom to form MnO5 square pyramids that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, and  a cornercorner with one Mn(5)O5 square pyramid. The corner-sharing octahedral tilt angles range from 3-9°. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(3), one Ca(7), one Cr(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(2), one Ca(6), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ca(1), one Ca(3), one Ca(5), one Ca(7), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(4), one Ca(6), one Cr(2), and one Mn(4) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Ca(3), one Ca(5), one Ca(7), one Cr(2), and one Mn(4) atom. In the sixth O site, O(6) is bonded to one Ca(1), one Ca(3), one Ca(5), one Ca(7), one Mn(5), and one Mn(6) atom to form distorted OCa4Mn2 octahedra that share  a faceface with one O(13)Ca4Mn2 octahedra,  a faceface with one O(20)Ca4Mn2 octahedra,  a faceface with one O(10)SrCa3Mn2 octahedra, and  a faceface with one O(18)SrCa3Mn2 octahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Sr(1), one Ca(2), one Cr(1), and one Cr(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Mn(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(2), and one Mn(5) atom. In the tenth O site, O(10) is bonded to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(3), and one Mn(6) atom to form distorted OSrCa3Mn2 octahedra that share corners with two equivalent O(13)Ca4Mn2 octahedra,  a faceface with one O(20)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(18)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-6°. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Ca(4), one Ca(5), one Ca(6), one Ca(7), one Mn(1), and one Mn(4) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to one Ca(4), one Ca(6), one Ca(7), one Mn(2), and one Mn(5) atom. In the thirteenth O site, O(13) is bonded to one Ca(4), one Ca(5), one Ca(6), one Ca(7), one Mn(3), and one Mn(6) atom to form distorted OCa4Mn2 octahedra that share corners with two equivalent O(10)SrCa3Mn2 octahedra,  a faceface with one O(20)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(18)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-6°. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(1), one Ca(4), one Cr(1), and one Mn(2) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Sr(1), one Ca(1), one Ca(4), one Ca(5), one Mn(1), and one Mn(3) atom. In the sixteenth O site, O(16) is bonded in a 6-coordinate geometry to one Ca(2), one Ca(3), one Ca(6), one Ca(7), one Mn(1), and one Mn(3) atom. In the seventeenth O site, O(17) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(1), one Ca(4), one Ca(5), one Cr(2), and one Mn(5) atom. In the eighteenth O site, O(18) is bonded to one Sr(1), one Ca(1), one Ca(4), one Ca(5), one Mn(4), and one Mn(6) atom to form distorted OSrCa3Mn2 octahedra that share corners with two equivalent O(20)Ca4Mn2 octahedra,  a faceface with one O(13)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(10)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 5-7°. In the nineteenth O site, O(19) is bonded in a 5-coordinate geometry to one Ca(2), one Ca(6), one Ca(7), one Cr(2), and one Mn(5) atom. In the twentieth O site, O(20) is bonded to one Ca(2), one Ca(3), one Ca(6), one Ca(7), one Mn(4), and one Mn(6) atom to form distorted OCa4Mn2 octahedra that share corners with two equivalent O(18)SrCa3Mn2 octahedra,  a faceface with one O(13)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(10)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 5-7°. is represented by the CIF file [CIF]
data_SrCa7Mn6Cr2O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.867
_cell_length_b   7.859
_cell_length_c   7.650
_cell_angle_alpha   88.468
_cell_angle_beta   88.553
_cell_angle_gamma   90.685
_symmetry_Int_Tables_number   1
_cell_volume   472.591
_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  0.247  0.257  0.257  1.0
  Ca  Ca1  1  0.272  0.281  0.700  1.0
  Ca  Ca2  1  0.252  0.732  0.269  1.0
  Ca  Ca3  1  0.257  0.720  0.710  1.0
  Ca  Ca4  1  0.734  0.255  0.262  1.0
  Ca  Ca5  1  0.720  0.262  0.715  1.0
  Ca  Ca6  1  0.741  0.746  0.270  1.0
  Ca  Ca7  1  0.728  0.734  0.725  1.0
  Mn  Mn8  1  0.001  0.001  0.522  1.0
  Mn  Mn9  1  0.997  0.489  0.001  1.0
  Mn  Mn10  1  0.998  0.507  0.493  1.0
  Mn  Mn11  1  0.508  0.000  0.493  1.0
  Mn  Mn12  1  0.503  0.506  0.997  1.0
  Mn  Mn13  1  0.505  0.505  0.489  1.0
  Cr  Cr14  1  0.028  0.018  0.980  1.0
  Cr  Cr15  1  0.474  0.996  0.004  1.0
  O  O16  1  0.940  0.927  0.793  1.0
  O  O17  1  0.013  0.532  0.243  1.0
  O  O18  1  0.005  0.521  0.749  1.0
  O  O19  1  0.545  0.013  0.242  1.0
  O  O20  1  0.525  1.000  0.752  1.0
  O  O21  1  0.503  0.508  0.743  1.0
  O  O22  1  0.233  0.956  0.062  1.0
  O  O23  1  0.250  0.003  0.515  1.0
  O  O24  1  0.254  0.511  0.007  1.0
  O  O25  1  0.262  0.503  0.484  1.0
  O  O26  1  0.763  0.007  0.477  1.0
  O  O27  1  0.748  0.515  0.029  1.0
  O  O28  1  0.744  0.502  0.475  1.0
  O  O29  1  0.959  0.218  0.058  1.0
  O  O30  1  0.006  0.249  0.519  1.0
  O  O31  1  0.007  0.764  0.469  1.0
  O  O32  1  0.505  0.255  0.009  1.0
  O  O33  1  0.501  0.263  0.485  1.0
  O  O34  1  0.524  0.750  0.033  1.0
  O  O35  1  0.501  0.744  0.472  1.0
[/CIF]
.
The crystal structure described by SrCa7Cr2Mn6O20 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P1 space group. Sr(1) is bonded in a 10-coordinate geometry to one O(10), one O(14), one O(15), one O(17), one O(18), one O(2), one O(4), one O(7), one O(8), and one O(9) atom. There are seven inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 9-coordinate geometry to one O(10), one O(15), one O(17), one O(18), one O(3), one O(5), one O(6), one O(8), and one O(9) atom. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(10), one O(16), one O(19), one O(2), one O(20), one O(7), one O(8), and one O(9) atom. In the third Ca site, Ca(3) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(16), one O(20), one O(3), one O(5), one O(6), one O(8), and one O(9) atom. In the fourth Ca site, Ca(4) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(15), one O(17), one O(18), and one O(4) atom. In the fifth Ca site, Ca(5) is bonded in a 8-coordinate geometry to one O(11), one O(13), one O(15), one O(17), one O(18), one O(3), one O(5), and one O(6) atom. In the sixth Ca site, Ca(6) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(13), one O(16), one O(19), one O(2), one O(20), and one O(4) atom. In the seventh Ca site, Ca(7) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(13), one O(16), one O(19), one O(20), one O(3), one O(5), and one O(6) atom. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a trigonal planar geometry to one O(1), one O(14), and one O(7) atom. In the second Cr site, Cr(2) is bonded to one O(17), one O(19), one O(4), one O(5), and one O(7) atom to form CrO5 trigonal bipyramids that share corners with two equivalent Mn(4)O6 octahedra and corners with two equivalent Mn(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 16-26°. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(15), one O(16), and one O(8) atom to form corner-sharing MnO5 square pyramids. The corner-sharing octahedral tilt angles range from 3-18°. In the second Mn site, Mn(2) is bonded to one O(12), one O(14), one O(2), one O(3), and one O(9) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(3)O6 octahedra and corners with two equivalent Mn(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 11-18°. In the third Mn site, Mn(3) is bonded to one O(10), one O(13), one O(15), one O(16), one O(2), and one O(3) atom to form corner-sharing MnO6 octahedra. In the fourth Mn site, Mn(4) is bonded to one O(11), one O(18), one O(20), one O(4), one O(5), and one O(8) atom to form MnO6 octahedra that share corners with two equivalent Mn(1)O5 square pyramids, corners with two equivalent Mn(6)O5 square pyramids, and corners with two equivalent Cr(2)O5 trigonal bipyramids. In the fifth Mn site, Mn(5) is bonded to one O(12), one O(17), one O(19), one O(6), and one O(9) atom to form MnO5 square pyramids that share  a cornercorner with one Mn(6)O5 square pyramid, corners with two equivalent Cr(2)O5 trigonal bipyramids, and corners with two equivalent Mn(2)O5 trigonal bipyramids. In the sixth Mn site, Mn(6) is bonded to one O(10), one O(13), one O(18), one O(20), and one O(6) atom to form MnO5 square pyramids that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, and  a cornercorner with one Mn(5)O5 square pyramid. The corner-sharing octahedral tilt angles range from 3-9°. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(3), one Ca(7), one Cr(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(2), one Ca(6), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ca(1), one Ca(3), one Ca(5), one Ca(7), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(4), one Ca(6), one Cr(2), and one Mn(4) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Ca(3), one Ca(5), one Ca(7), one Cr(2), and one Mn(4) atom. In the sixth O site, O(6) is bonded to one Ca(1), one Ca(3), one Ca(5), one Ca(7), one Mn(5), and one Mn(6) atom to form distorted OCa4Mn2 octahedra that share  a faceface with one O(13)Ca4Mn2 octahedra,  a faceface with one O(20)Ca4Mn2 octahedra,  a faceface with one O(10)SrCa3Mn2 octahedra, and  a faceface with one O(18)SrCa3Mn2 octahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Sr(1), one Ca(2), one Cr(1), and one Cr(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Mn(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(2), and one Mn(5) atom. In the tenth O site, O(10) is bonded to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(3), and one Mn(6) atom to form distorted OSrCa3Mn2 octahedra that share corners with two equivalent O(13)Ca4Mn2 octahedra,  a faceface with one O(20)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(18)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-6°. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Ca(4), one Ca(5), one Ca(6), one Ca(7), one Mn(1), and one Mn(4) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to one Ca(4), one Ca(6), one Ca(7), one Mn(2), and one Mn(5) atom. In the thirteenth O site, O(13) is bonded to one Ca(4), one Ca(5), one Ca(6), one Ca(7), one Mn(3), and one Mn(6) atom to form distorted OCa4Mn2 octahedra that share corners with two equivalent O(10)SrCa3Mn2 octahedra,  a faceface with one O(20)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(18)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-6°. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(1), one Ca(4), one Cr(1), and one Mn(2) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Sr(1), one Ca(1), one Ca(4), one Ca(5), one Mn(1), and one Mn(3) atom. In the sixteenth O site, O(16) is bonded in a 6-coordinate geometry to one Ca(2), one Ca(3), one Ca(6), one Ca(7), one Mn(1), and one Mn(3) atom. In the seventeenth O site, O(17) is bonded in a 2-coordinate geometry to one Sr(1), one Ca(1), one Ca(4), one Ca(5), one Cr(2), and one Mn(5) atom. In the eighteenth O site, O(18) is bonded to one Sr(1), one Ca(1), one Ca(4), one Ca(5), one Mn(4), and one Mn(6) atom to form distorted OSrCa3Mn2 octahedra that share corners with two equivalent O(20)Ca4Mn2 octahedra,  a faceface with one O(13)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(10)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 5-7°. In the nineteenth O site, O(19) is bonded in a 5-coordinate geometry to one Ca(2), one Ca(6), one Ca(7), one Cr(2), and one Mn(5) atom. In the twentieth O site, O(20) is bonded to one Ca(2), one Ca(3), one Ca(6), one Ca(7), one Mn(4), and one Mn(6) atom to form distorted OCa4Mn2 octahedra that share corners with two equivalent O(18)SrCa3Mn2 octahedra,  a faceface with one O(13)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4Mn2 octahedra, and  a faceface with one O(10)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 5-7°. is represented by the CIF file [CIF]
data_SrCa7Mn6Cr2O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.867
_cell_length_b   7.859
_cell_length_c   7.650
_cell_angle_alpha   88.468
_cell_angle_beta   88.553
_cell_angle_gamma   90.685
_symmetry_Int_Tables_number   1
_cell_volume   472.591
_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  0.247  0.257  0.257  1.0
  Ca  Ca1  1  0.272  0.281  0.700  1.0
  Ca  Ca2  1  0.252  0.732  0.269  1.0
  Ca  Ca3  1  0.257  0.720  0.710  1.0
  Ca  Ca4  1  0.734  0.255  0.262  1.0
  Ca  Ca5  1  0.720  0.262  0.715  1.0
  Ca  Ca6  1  0.741  0.746  0.270  1.0
  Ca  Ca7  1  0.728  0.734  0.725  1.0
  Mn  Mn8  1  0.001  0.001  0.522  1.0
  Mn  Mn9  1  0.997  0.489  0.001  1.0
  Mn  Mn10  1  0.998  0.507  0.493  1.0
  Mn  Mn11  1  0.508  0.000  0.493  1.0
  Mn  Mn12  1  0.503  0.506  0.997  1.0
  Mn  Mn13  1  0.505  0.505  0.489  1.0
  Cr  Cr14  1  0.028  0.018  0.980  1.0
  Cr  Cr15  1  0.474  0.996  0.004  1.0
  O  O16  1  0.940  0.927  0.793  1.0
  O  O17  1  0.013  0.532  0.243  1.0
  O  O18  1  0.005  0.521  0.749  1.0
  O  O19  1  0.545  0.013  0.242  1.0
  O  O20  1  0.525  1.000  0.752  1.0
  O  O21  1  0.503  0.508  0.743  1.0
  O  O22  1  0.233  0.956  0.062  1.0
  O  O23  1  0.250  0.003  0.515  1.0
  O  O24  1  0.254  0.511  0.007  1.0
  O  O25  1  0.262  0.503  0.484  1.0
  O  O26  1  0.763  0.007  0.477  1.0
  O  O27  1  0.748  0.515  0.029  1.0
  O  O28  1  0.744  0.502  0.475  1.0
  O  O29  1  0.959  0.218  0.058  1.0
  O  O30  1  0.006  0.249  0.519  1.0
  O  O31  1  0.007  0.764  0.469  1.0
  O  O32  1  0.505  0.255  0.009  1.0
  O  O33  1  0.501  0.263  0.485  1.0
  O  O34  1  0.524  0.750  0.033  1.0
  O  O35  1  0.501  0.744  0.472  1.0
[/CIF]
.