The material structure described by SrCa7Mn6Al2O21 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a distorted q6 geometry to one O(3), two equivalent O(1), four equivalent O(4), and four equivalent O(5) atoms. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted q6 geometry to two equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms. In the second Ca site, Ca(2) is bonded in a distorted q6 geometry to one O(3), two equivalent O(1), two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. In the third Ca site, Ca(3) is bonded in a distorted q6 geometry to two equivalent O(2), two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. In the fourth Ca site, Ca(4) is bonded in a distorted q6 geometry to one O(3), two equivalent O(1), four equivalent O(6), and four equivalent O(7) atoms. In the fifth Ca site, Ca(5) is bonded in a distorted q6 geometry to two equivalent O(2), four equivalent O(6), and four equivalent O(7) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°. In the second Mn site, Mn(2) is bonded to one O(3), two equivalent O(5), and two equivalent O(7) atoms to form MnO5 square pyramids that share corners with four equivalent Mn(1)O6 octahedra and  a cornercorner with one Mn(2)O5 square pyramid. The corner-sharing octahedral tilt angles are 9°. Al(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(4) and two equivalent O(6) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Sr(1), one Ca(4), two equivalent Ca(2), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to one Ca(1), one Ca(5), two equivalent Ca(3), and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded to one Sr(1), one Ca(4), two equivalent Ca(2), and two equivalent Mn(2) atoms to form distorted OSrCa3Mn2 octahedra that share corners with eight equivalent O(6)Ca4MnAl octahedra, corners with eight equivalent O(4)SrCa3MnAl octahedra, faces with four equivalent O(7)Ca4Mn2 octahedra, and faces with four equivalent O(5)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. In the fourth O site, O(4) is bonded to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Al(1) atom to form distorted OSrCa3MnAl octahedra that share corners with two equivalent O(7)Ca4Mn2 octahedra, corners with two equivalent O(3)SrCa3Mn2 octahedra, corners with two equivalent O(4)SrCa3MnAl octahedra, corners with four equivalent O(6)Ca4MnAl octahedra, corners with six equivalent O(5)SrCa3Mn2 octahedra, edges with two equivalent O(5)SrCa3Mn2 octahedra, edges with two equivalent O(4)SrCa3MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 1-70°. In the fifth O site, O(5) is bonded to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Mn(2) atom to form distorted OSrCa3Mn2 octahedra that share corners with two equivalent O(6)Ca4MnAl octahedra, corners with two equivalent O(5)SrCa3Mn2 octahedra, corners with four equivalent O(7)Ca4Mn2 octahedra, corners with six equivalent O(4)SrCa3MnAl octahedra, edges with two equivalent O(5)SrCa3Mn2 octahedra, edges with two equivalent O(4)SrCa3MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(3)SrCa3Mn2 octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 3-66°. In the sixth O site, O(6) is bonded to one Ca(2), one Ca(3), one Ca(4), one Ca(5), one Mn(1), and one Al(1) atom to form distorted OCa4MnAl octahedra that share corners with two equivalent O(6)Ca4MnAl octahedra, corners with two equivalent O(3)SrCa3Mn2 octahedra, corners with two equivalent O(5)SrCa3Mn2 octahedra, corners with four equivalent O(4)SrCa3MnAl octahedra, corners with six equivalent O(7)Ca4Mn2 octahedra, edges with two equivalent O(7)Ca4Mn2 octahedra, edges with two equivalent O(6)Ca4MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 1-70°. In the seventh O site, O(7) is bonded to one Ca(2), one Ca(3), one Ca(4), one Ca(5), one Mn(1), and one Mn(2) atom to form distorted OCa4Mn2 octahedra that share corners with two equivalent O(7)Ca4Mn2 octahedra, corners with two equivalent O(4)SrCa3MnAl octahedra, corners with four equivalent O(5)SrCa3Mn2 octahedra, corners with six equivalent O(6)Ca4MnAl octahedra, edges with two equivalent O(7)Ca4Mn2 octahedra, edges with two equivalent O(6)Ca4MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(3)SrCa3Mn2 octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 3-65°. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrCa7Mn6Al2O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.748
_cell_length_b   7.748
_cell_length_c   7.470
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   89.935
_symmetry_Int_Tables_number   1
_cell_volume   448.404
_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  0.258  0.258  0.250  1.0
  Ca  Ca1  1  0.252  0.252  0.750  1.0
  Ca  Ca2  1  0.263  0.739  0.250  1.0
  Ca  Ca3  1  0.252  0.749  0.750  1.0
  Ca  Ca4  1  0.739  0.263  0.250  1.0
  Ca  Ca5  1  0.749  0.252  0.750  1.0
  Ca  Ca6  1  0.738  0.738  0.250  1.0
  Ca  Ca7  1  0.748  0.748  0.750  1.0
  Mn  Mn8  1  1.000  0.501  0.997  1.0
  Mn  Mn9  1  1.000  0.501  0.503  1.0
  Mn  Mn10  1  0.501  1.000  0.997  1.0
  Mn  Mn11  1  0.501  1.000  0.503  1.0
  Mn  Mn12  1  0.501  0.501  0.998  1.0
  Mn  Mn13  1  0.501  0.501  0.502  1.0
  Al  Al14  1  0.999  0.999  0.001  1.0
  Al  Al15  1  0.999  0.999  0.499  1.0
  O  O16  1  0.996  0.502  0.250  1.0
  O  O17  1  0.999  0.501  0.750  1.0
  O  O18  1  0.502  0.996  0.250  1.0
  O  O19  1  0.501  0.999  0.750  1.0
  O  O20  1  0.504  0.504  0.250  1.0
  O  O21  1  0.234  0.998  0.997  1.0
  O  O22  1  0.234  0.998  0.503  1.0
  O  O23  1  0.256  0.502  0.976  1.0
  O  O24  1  0.256  0.502  0.524  1.0
  O  O25  1  0.765  0.999  1.000  1.0
  O  O26  1  0.765  0.999  0.500  1.0
  O  O27  1  0.744  0.501  0.978  1.0
  O  O28  1  0.744  0.501  0.522  1.0
  O  O29  1  0.998  0.234  0.997  1.0
  O  O30  1  0.998  0.234  0.503  1.0
  O  O31  1  0.999  0.765  1.000  1.0
  O  O32  1  0.999  0.765  0.500  1.0
  O  O33  1  0.502  0.256  0.976  1.0
  O  O34  1  0.502  0.256  0.524  1.0
  O  O35  1  0.501  0.744  0.978  1.0
  O  O36  1  0.501  0.744  0.522  1.0
[/CIF]
.
The material structure described by SrCa7Mn6Al2O21 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a distorted q6 geometry to one O(3), two equivalent O(1), four equivalent O(4), and four equivalent O(5) atoms. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted q6 geometry to two equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms. In the second Ca site, Ca(2) is bonded in a distorted q6 geometry to one O(3), two equivalent O(1), two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. In the third Ca site, Ca(3) is bonded in a distorted q6 geometry to two equivalent O(2), two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. In the fourth Ca site, Ca(4) is bonded in a distorted q6 geometry to one O(3), two equivalent O(1), four equivalent O(6), and four equivalent O(7) atoms. In the fifth Ca site, Ca(5) is bonded in a distorted q6 geometry to two equivalent O(2), four equivalent O(6), and four equivalent O(7) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°. In the second Mn site, Mn(2) is bonded to one O(3), two equivalent O(5), and two equivalent O(7) atoms to form MnO5 square pyramids that share corners with four equivalent Mn(1)O6 octahedra and  a cornercorner with one Mn(2)O5 square pyramid. The corner-sharing octahedral tilt angles are 9°. Al(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(4) and two equivalent O(6) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Sr(1), one Ca(4), two equivalent Ca(2), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to one Ca(1), one Ca(5), two equivalent Ca(3), and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded to one Sr(1), one Ca(4), two equivalent Ca(2), and two equivalent Mn(2) atoms to form distorted OSrCa3Mn2 octahedra that share corners with eight equivalent O(6)Ca4MnAl octahedra, corners with eight equivalent O(4)SrCa3MnAl octahedra, faces with four equivalent O(7)Ca4Mn2 octahedra, and faces with four equivalent O(5)SrCa3Mn2 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. In the fourth O site, O(4) is bonded to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Al(1) atom to form distorted OSrCa3MnAl octahedra that share corners with two equivalent O(7)Ca4Mn2 octahedra, corners with two equivalent O(3)SrCa3Mn2 octahedra, corners with two equivalent O(4)SrCa3MnAl octahedra, corners with four equivalent O(6)Ca4MnAl octahedra, corners with six equivalent O(5)SrCa3Mn2 octahedra, edges with two equivalent O(5)SrCa3Mn2 octahedra, edges with two equivalent O(4)SrCa3MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 1-70°. In the fifth O site, O(5) is bonded to one Sr(1), one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Mn(2) atom to form distorted OSrCa3Mn2 octahedra that share corners with two equivalent O(6)Ca4MnAl octahedra, corners with two equivalent O(5)SrCa3Mn2 octahedra, corners with four equivalent O(7)Ca4Mn2 octahedra, corners with six equivalent O(4)SrCa3MnAl octahedra, edges with two equivalent O(5)SrCa3Mn2 octahedra, edges with two equivalent O(4)SrCa3MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(3)SrCa3Mn2 octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 3-66°. In the sixth O site, O(6) is bonded to one Ca(2), one Ca(3), one Ca(4), one Ca(5), one Mn(1), and one Al(1) atom to form distorted OCa4MnAl octahedra that share corners with two equivalent O(6)Ca4MnAl octahedra, corners with two equivalent O(3)SrCa3Mn2 octahedra, corners with two equivalent O(5)SrCa3Mn2 octahedra, corners with four equivalent O(4)SrCa3MnAl octahedra, corners with six equivalent O(7)Ca4Mn2 octahedra, edges with two equivalent O(7)Ca4Mn2 octahedra, edges with two equivalent O(6)Ca4MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 1-70°. In the seventh O site, O(7) is bonded to one Ca(2), one Ca(3), one Ca(4), one Ca(5), one Mn(1), and one Mn(2) atom to form distorted OCa4Mn2 octahedra that share corners with two equivalent O(7)Ca4Mn2 octahedra, corners with two equivalent O(4)SrCa3MnAl octahedra, corners with four equivalent O(5)SrCa3Mn2 octahedra, corners with six equivalent O(6)Ca4MnAl octahedra, edges with two equivalent O(7)Ca4Mn2 octahedra, edges with two equivalent O(6)Ca4MnAl octahedra,  a faceface with one O(7)Ca4Mn2 octahedra,  a faceface with one O(6)Ca4MnAl octahedra,  a faceface with one O(3)SrCa3Mn2 octahedra,  a faceface with one O(5)SrCa3Mn2 octahedra, and  a faceface with one O(4)SrCa3MnAl octahedra. The corner-sharing octahedral tilt angles range from 3-65°. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrCa7Mn6Al2O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.748
_cell_length_b   7.748
_cell_length_c   7.470
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   89.935
_symmetry_Int_Tables_number   1
_cell_volume   448.404
_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  0.258  0.258  0.250  1.0
  Ca  Ca1  1  0.252  0.252  0.750  1.0
  Ca  Ca2  1  0.263  0.739  0.250  1.0
  Ca  Ca3  1  0.252  0.749  0.750  1.0
  Ca  Ca4  1  0.739  0.263  0.250  1.0
  Ca  Ca5  1  0.749  0.252  0.750  1.0
  Ca  Ca6  1  0.738  0.738  0.250  1.0
  Ca  Ca7  1  0.748  0.748  0.750  1.0
  Mn  Mn8  1  1.000  0.501  0.997  1.0
  Mn  Mn9  1  1.000  0.501  0.503  1.0
  Mn  Mn10  1  0.501  1.000  0.997  1.0
  Mn  Mn11  1  0.501  1.000  0.503  1.0
  Mn  Mn12  1  0.501  0.501  0.998  1.0
  Mn  Mn13  1  0.501  0.501  0.502  1.0
  Al  Al14  1  0.999  0.999  0.001  1.0
  Al  Al15  1  0.999  0.999  0.499  1.0
  O  O16  1  0.996  0.502  0.250  1.0
  O  O17  1  0.999  0.501  0.750  1.0
  O  O18  1  0.502  0.996  0.250  1.0
  O  O19  1  0.501  0.999  0.750  1.0
  O  O20  1  0.504  0.504  0.250  1.0
  O  O21  1  0.234  0.998  0.997  1.0
  O  O22  1  0.234  0.998  0.503  1.0
  O  O23  1  0.256  0.502  0.976  1.0
  O  O24  1  0.256  0.502  0.524  1.0
  O  O25  1  0.765  0.999  1.000  1.0
  O  O26  1  0.765  0.999  0.500  1.0
  O  O27  1  0.744  0.501  0.978  1.0
  O  O28  1  0.744  0.501  0.522  1.0
  O  O29  1  0.998  0.234  0.997  1.0
  O  O30  1  0.998  0.234  0.503  1.0
  O  O31  1  0.999  0.765  1.000  1.0
  O  O32  1  0.999  0.765  0.500  1.0
  O  O33  1  0.502  0.256  0.976  1.0
  O  O34  1  0.502  0.256  0.524  1.0
  O  O35  1  0.501  0.744  0.978  1.0
  O  O36  1  0.501  0.744  0.522  1.0
[/CIF]
.