The crystal structure described by Ca8Mo7O20 crystallizes in the tetragonal I4/m space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form MoO5 square pyramids that share  a cornercorner with one Mo(3)O6 octahedra, corners with two equivalent Mo(1)O5 square pyramids, and corners with two equivalent Mo(2)O5 square pyramids. The corner-sharing octahedral tilt angles are 24°. In the second Mo site, Mo(2) is bonded to one O(5) and four equivalent O(2) atoms to form MoO5 square pyramids that share  a cornercorner with one Mo(3)O6 octahedra and corners with four equivalent Mo(1)O5 square pyramids. The corner-sharing octahedra are not tilted. In the third Mo site, Mo(3) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form corner-sharing MoO6 octahedra. There are five inequivalent O sites. In the first O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1), one Mo(1), and one Mo(2) atom. In the second O site, O(3) is bonded to four equivalent Ca(1) atoms to form OCa4 tetrahedra that share corners with four equivalent O(5)Ca4Mo2 octahedra, corners with eight equivalent O(4)Ca4Mo2 octahedra, and corners with four equivalent O(1)Ca2Mo2 trigonal pyramids. The corner-sharing octahedral tilt angles range from 20-64°. In the third O site, O(4) is bonded to four equivalent Ca(1), one Mo(1), and one Mo(3) atom to form distorted OCa4Mo2 octahedra that share  a cornercorner with one O(4)Ca4Mo2 octahedra, corners with four equivalent O(3)Ca4 tetrahedra,  a cornercorner with one O(1)Ca2Mo2 trigonal pyramid,  an edgeedge with one O(1)Ca2Mo2 trigonal pyramid, faces with two equivalent O(4)Ca4Mo2 octahedra, faces with two equivalent O(5)Ca4Mo2 octahedra, and  a faceface with one O(1)Ca2Mo2 trigonal pyramid. The corner-sharing octahedra are not tilted. In the fourth O site, O(5) is bonded to four equivalent Ca(1), one Mo(2), and one Mo(3) atom to form OCa4Mo2 octahedra that share  a cornercorner with one O(5)Ca4Mo2 octahedra, corners with four equivalent O(3)Ca4 tetrahedra, corners with four equivalent O(1)Ca2Mo2 trigonal pyramids, and faces with four equivalent O(4)Ca4Mo2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(1) is bonded to two equivalent Ca(1) and two equivalent Mo(1) atoms to form OCa2Mo2 trigonal pyramids that share  a cornercorner with one O(4)Ca4Mo2 octahedra, corners with two equivalent O(5)Ca4Mo2 octahedra, corners with two equivalent O(3)Ca4 tetrahedra, corners with two equivalent O(1)Ca2Mo2 trigonal pyramids,  an edgeedge with one O(4)Ca4Mo2 octahedra, and  a faceface with one O(4)Ca4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 49-88°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca8Mo7O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.644
_cell_length_b   8.644
_cell_length_c   8.644
_cell_angle_alpha   119.955
_cell_angle_beta   119.955
_cell_angle_gamma   90.078
_symmetry_Int_Tables_number   1
_cell_volume   457.047
_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  0.553  0.916  0.773  1.0
  Ca  Ca1  1  0.447  0.084  0.227  1.0
  Ca  Ca2  1  0.143  0.780  0.227  1.0
  Ca  Ca3  1  0.780  0.553  0.637  1.0
  Ca  Ca4  1  0.857  0.220  0.773  1.0
  Ca  Ca5  1  0.220  0.447  0.363  1.0
  Ca  Ca6  1  0.916  0.143  0.363  1.0
  Ca  Ca7  1  0.084  0.857  0.637  1.0
  Mo  Mo8  1  0.694  0.376  0.070  1.0
  Mo  Mo9  1  0.306  0.624  0.930  1.0
  Mo  Mo10  1  0.624  0.694  0.318  1.0
  Mo  Mo11  1  0.376  0.306  0.682  1.0
  Mo  Mo12  1  0.659  0.659  0.000  1.0
  Mo  Mo13  1  0.341  0.341  0.000  1.0
  Mo  Mo14  1  0.000  0.000  0.000  1.0
  O  O15  1  0.559  0.171  0.730  1.0
  O  O16  1  0.441  0.829  0.270  1.0
  O  O17  1  0.829  0.559  0.388  1.0
  O  O18  1  0.171  0.441  0.612  1.0
  O  O19  1  0.483  0.815  0.965  1.0
  O  O20  1  0.517  0.185  0.035  1.0
  O  O21  1  0.850  0.519  0.035  1.0
  O  O22  1  0.519  0.483  0.668  1.0
  O  O23  1  0.150  0.481  0.965  1.0
  O  O24  1  0.481  0.517  0.332  1.0
  O  O25  1  0.815  0.850  0.332  1.0
  O  O26  1  0.185  0.150  0.668  1.0
  O  O27  1  0.250  0.750  0.500  1.0
  O  O28  1  0.750  0.250  0.500  1.0
  O  O29  1  0.885  0.222  0.107  1.0
  O  O30  1  0.115  0.778  0.893  1.0
  O  O31  1  0.778  0.885  0.664  1.0
  O  O32  1  0.222  0.115  0.336  1.0
  O  O33  1  0.828  0.828  0.000  1.0
  O  O34  1  0.172  0.172  0.000  1.0
[/CIF]
.
The crystal structure described by Ca8Mo7O20 crystallizes in the tetragonal I4/m space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form MoO5 square pyramids that share  a cornercorner with one Mo(3)O6 octahedra, corners with two equivalent Mo(1)O5 square pyramids, and corners with two equivalent Mo(2)O5 square pyramids. The corner-sharing octahedral tilt angles are 24°. In the second Mo site, Mo(2) is bonded to one O(5) and four equivalent O(2) atoms to form MoO5 square pyramids that share  a cornercorner with one Mo(3)O6 octahedra and corners with four equivalent Mo(1)O5 square pyramids. The corner-sharing octahedra are not tilted. In the third Mo site, Mo(3) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form corner-sharing MoO6 octahedra. There are five inequivalent O sites. In the first O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1), one Mo(1), and one Mo(2) atom. In the second O site, O(3) is bonded to four equivalent Ca(1) atoms to form OCa4 tetrahedra that share corners with four equivalent O(5)Ca4Mo2 octahedra, corners with eight equivalent O(4)Ca4Mo2 octahedra, and corners with four equivalent O(1)Ca2Mo2 trigonal pyramids. The corner-sharing octahedral tilt angles range from 20-64°. In the third O site, O(4) is bonded to four equivalent Ca(1), one Mo(1), and one Mo(3) atom to form distorted OCa4Mo2 octahedra that share  a cornercorner with one O(4)Ca4Mo2 octahedra, corners with four equivalent O(3)Ca4 tetrahedra,  a cornercorner with one O(1)Ca2Mo2 trigonal pyramid,  an edgeedge with one O(1)Ca2Mo2 trigonal pyramid, faces with two equivalent O(4)Ca4Mo2 octahedra, faces with two equivalent O(5)Ca4Mo2 octahedra, and  a faceface with one O(1)Ca2Mo2 trigonal pyramid. The corner-sharing octahedra are not tilted. In the fourth O site, O(5) is bonded to four equivalent Ca(1), one Mo(2), and one Mo(3) atom to form OCa4Mo2 octahedra that share  a cornercorner with one O(5)Ca4Mo2 octahedra, corners with four equivalent O(3)Ca4 tetrahedra, corners with four equivalent O(1)Ca2Mo2 trigonal pyramids, and faces with four equivalent O(4)Ca4Mo2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(1) is bonded to two equivalent Ca(1) and two equivalent Mo(1) atoms to form OCa2Mo2 trigonal pyramids that share  a cornercorner with one O(4)Ca4Mo2 octahedra, corners with two equivalent O(5)Ca4Mo2 octahedra, corners with two equivalent O(3)Ca4 tetrahedra, corners with two equivalent O(1)Ca2Mo2 trigonal pyramids,  an edgeedge with one O(4)Ca4Mo2 octahedra, and  a faceface with one O(4)Ca4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 49-88°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca8Mo7O20
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.644
_cell_length_b   8.644
_cell_length_c   8.644
_cell_angle_alpha   119.955
_cell_angle_beta   119.955
_cell_angle_gamma   90.078
_symmetry_Int_Tables_number   1
_cell_volume   457.047
_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  0.553  0.916  0.773  1.0
  Ca  Ca1  1  0.447  0.084  0.227  1.0
  Ca  Ca2  1  0.143  0.780  0.227  1.0
  Ca  Ca3  1  0.780  0.553  0.637  1.0
  Ca  Ca4  1  0.857  0.220  0.773  1.0
  Ca  Ca5  1  0.220  0.447  0.363  1.0
  Ca  Ca6  1  0.916  0.143  0.363  1.0
  Ca  Ca7  1  0.084  0.857  0.637  1.0
  Mo  Mo8  1  0.694  0.376  0.070  1.0
  Mo  Mo9  1  0.306  0.624  0.930  1.0
  Mo  Mo10  1  0.624  0.694  0.318  1.0
  Mo  Mo11  1  0.376  0.306  0.682  1.0
  Mo  Mo12  1  0.659  0.659  0.000  1.0
  Mo  Mo13  1  0.341  0.341  0.000  1.0
  Mo  Mo14  1  0.000  0.000  0.000  1.0
  O  O15  1  0.559  0.171  0.730  1.0
  O  O16  1  0.441  0.829  0.270  1.0
  O  O17  1  0.829  0.559  0.388  1.0
  O  O18  1  0.171  0.441  0.612  1.0
  O  O19  1  0.483  0.815  0.965  1.0
  O  O20  1  0.517  0.185  0.035  1.0
  O  O21  1  0.850  0.519  0.035  1.0
  O  O22  1  0.519  0.483  0.668  1.0
  O  O23  1  0.150  0.481  0.965  1.0
  O  O24  1  0.481  0.517  0.332  1.0
  O  O25  1  0.815  0.850  0.332  1.0
  O  O26  1  0.185  0.150  0.668  1.0
  O  O27  1  0.250  0.750  0.500  1.0
  O  O28  1  0.750  0.250  0.500  1.0
  O  O29  1  0.885  0.222  0.107  1.0
  O  O30  1  0.115  0.778  0.893  1.0
  O  O31  1  0.778  0.885  0.664  1.0
  O  O32  1  0.222  0.115  0.336  1.0
  O  O33  1  0.828  0.828  0.000  1.0
  O  O34  1  0.172  0.172  0.000  1.0
[/CIF]
.