The structure described by Ca2Cr9O13 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(3), one O(6), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(6) and four equivalent O(7) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 7-10°. In the second Cr site, Cr(2) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the third Cr site, Cr(3) is bonded to one O(5), two equivalent O(6), and three equivalent O(7) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the fourth Cr site, Cr(4) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the fifth Cr site, Cr(5) is bonded to one O(2), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 3-52°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Cr(4) and four equivalent Cr(2) atoms to form OCr6 octahedra that share corners with four equivalent O(3)CaCr5 octahedra, corners with two equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with six equivalent O(3)CaCr5 octahedra, and edges with four equivalent O(4)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cr(4), and one Cr(5) atom to form distorted OCa2Cr2 tetrahedra that share  a cornercorner with one O(1)Cr6 octahedra,  a cornercorner with one O(7)Cr6 octahedra, corners with four equivalent O(4)Ca2Cr3 square pyramids, corners with four equivalent O(5)Ca2Cr3 square pyramids, corners with two equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(3)CaCr5 octahedra, edges with two equivalent O(6)CaCr5 octahedra,  an edgeedge with one O(4)Ca2Cr3 square pyramid, and  an edgeedge with one O(5)Ca2Cr3 square pyramid. The corner-sharing octahedral tilt angles range from 2-6°. In the third O site, O(3) is bonded to one Ca(1), two equivalent Cr(4), and three equivalent Cr(2) atoms to form distorted OCaCr5 octahedra that share  a cornercorner with one O(6)CaCr5 octahedra, corners with two equivalent O(1)Cr6 octahedra, corners with two equivalent O(5)Ca2Cr3 square pyramids, corners with three equivalent O(4)Ca2Cr3 square pyramids, edges with three equivalent O(1)Cr6 octahedra, edges with four equivalent O(3)CaCr5 octahedra, edges with three equivalent O(4)Ca2Cr3 square pyramids, and edges with two equivalent O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 2-55°. In the fourth O site, O(4) is bonded to two equivalent Ca(1), one Cr(2), and two equivalent Cr(4) atoms to form distorted OCa2Cr3 square pyramids that share corners with two equivalent O(6)CaCr5 octahedra, corners with three equivalent O(3)CaCr5 octahedra, corners with two equivalent O(5)Ca2Cr3 square pyramids, corners with four equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with three equivalent O(3)CaCr5 octahedra,  an edgeedge with one O(5)Ca2Cr3 square pyramid, edges with two equivalent O(4)Ca2Cr3 square pyramids, and  an edgeedge with one O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 9-42°. In the fifth O site, O(5) is bonded to two equivalent Ca(1), one Cr(3), and two equivalent Cr(5) atoms to form distorted OCa2Cr3 square pyramids that share  a cornercorner with one O(7)Cr6 octahedra, corners with two equivalent O(3)CaCr5 octahedra, corners with two equivalent O(6)CaCr5 octahedra, corners with two equivalent O(4)Ca2Cr3 square pyramids, corners with four equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(7)Cr6 octahedra, edges with three equivalent O(6)CaCr5 octahedra,  an edgeedge with one O(4)Ca2Cr3 square pyramid, edges with two equivalent O(5)Ca2Cr3 square pyramids, and  an edgeedge with one O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 8-42°. In the sixth O site, O(6) is bonded to one Ca(1), one Cr(1), two equivalent Cr(3), and two equivalent Cr(5) atoms to form distorted OCaCr5 octahedra that share  a cornercorner with one O(3)CaCr5 octahedra,  a cornercorner with one O(6)CaCr5 octahedra, corners with two equivalent O(7)Cr6 octahedra, corners with two equivalent O(4)Ca2Cr3 square pyramids, corners with two equivalent O(5)Ca2Cr3 square pyramids, edges with two equivalent O(6)CaCr5 octahedra, edges with five equivalent O(7)Cr6 octahedra, edges with three equivalent O(5)Ca2Cr3 square pyramids, and edges with two equivalent O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 0-55°. In the seventh O site, O(7) is bonded to one Cr(5), two equivalent Cr(1), and three equivalent Cr(3) atoms to form OCr6 octahedra that share corners with two equivalent O(6)CaCr5 octahedra, corners with two equivalent O(7)Cr6 octahedra,  a cornercorner with one O(5)Ca2Cr3 square pyramid,  a cornercorner with one O(2)Ca2Cr2 tetrahedra, edges with five equivalent O(6)CaCr5 octahedra, edges with five equivalent O(7)Cr6 octahedra, and edges with two equivalent O(5)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. is represented by the CIF file [CIF]
data_Ca2Cr9O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.122
_cell_length_b   5.372
_cell_length_c   16.627
_cell_angle_alpha   81.388
_cell_angle_beta   85.249
_cell_angle_gamma   75.741
_symmetry_Int_Tables_number   1
_cell_volume   266.876
_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  0.752  0.234  0.230  1.0
  Ca  Ca1  1  0.248  0.766  0.770  1.0
  Cr  Cr2  1  0.500  0.500  0.500  1.0
  Cr  Cr3  1  0.353  0.258  0.040  1.0
  Cr  Cr4  1  0.647  0.742  0.960  1.0
  Cr  Cr5  1  0.247  0.095  0.421  1.0
  Cr  Cr6  1  0.753  0.905  0.579  1.0
  Cr  Cr7  1  0.046  0.772  0.122  1.0
  Cr  Cr8  1  0.954  0.228  0.878  1.0
  Cr  Cr9  1  0.994  0.677  0.338  1.0
  Cr  Cr10  1  0.006  0.323  0.662  1.0
  O  O11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.102  0.557  0.230  1.0
  O  O13  1  0.898  0.443  0.770  1.0
  O  O14  1  0.661  0.547  0.079  1.0
  O  O15  1  0.339  0.453  0.921  1.0
  O  O16  1  0.420  0.014  0.144  1.0
  O  O17  1  0.580  0.986  0.856  1.0
  O  O18  1  0.384  0.936  0.316  1.0
  O  O19  1  0.616  0.064  0.684  1.0
  O  O20  1  0.564  0.415  0.379  1.0
  O  O21  1  0.436  0.585  0.621  1.0
  O  O22  1  0.949  0.791  0.461  1.0
  O  O23  1  0.051  0.209  0.539  1.0
[/CIF]
.
The structure described by Ca2Cr9O13 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(3), one O(6), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(6) and four equivalent O(7) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 7-10°. In the second Cr site, Cr(2) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the third Cr site, Cr(3) is bonded to one O(5), two equivalent O(6), and three equivalent O(7) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the fourth Cr site, Cr(4) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the fifth Cr site, Cr(5) is bonded to one O(2), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 3-52°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Cr(4) and four equivalent Cr(2) atoms to form OCr6 octahedra that share corners with four equivalent O(3)CaCr5 octahedra, corners with two equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with six equivalent O(3)CaCr5 octahedra, and edges with four equivalent O(4)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cr(4), and one Cr(5) atom to form distorted OCa2Cr2 tetrahedra that share  a cornercorner with one O(1)Cr6 octahedra,  a cornercorner with one O(7)Cr6 octahedra, corners with four equivalent O(4)Ca2Cr3 square pyramids, corners with four equivalent O(5)Ca2Cr3 square pyramids, corners with two equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(3)CaCr5 octahedra, edges with two equivalent O(6)CaCr5 octahedra,  an edgeedge with one O(4)Ca2Cr3 square pyramid, and  an edgeedge with one O(5)Ca2Cr3 square pyramid. The corner-sharing octahedral tilt angles range from 2-6°. In the third O site, O(3) is bonded to one Ca(1), two equivalent Cr(4), and three equivalent Cr(2) atoms to form distorted OCaCr5 octahedra that share  a cornercorner with one O(6)CaCr5 octahedra, corners with two equivalent O(1)Cr6 octahedra, corners with two equivalent O(5)Ca2Cr3 square pyramids, corners with three equivalent O(4)Ca2Cr3 square pyramids, edges with three equivalent O(1)Cr6 octahedra, edges with four equivalent O(3)CaCr5 octahedra, edges with three equivalent O(4)Ca2Cr3 square pyramids, and edges with two equivalent O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 2-55°. In the fourth O site, O(4) is bonded to two equivalent Ca(1), one Cr(2), and two equivalent Cr(4) atoms to form distorted OCa2Cr3 square pyramids that share corners with two equivalent O(6)CaCr5 octahedra, corners with three equivalent O(3)CaCr5 octahedra, corners with two equivalent O(5)Ca2Cr3 square pyramids, corners with four equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with three equivalent O(3)CaCr5 octahedra,  an edgeedge with one O(5)Ca2Cr3 square pyramid, edges with two equivalent O(4)Ca2Cr3 square pyramids, and  an edgeedge with one O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 9-42°. In the fifth O site, O(5) is bonded to two equivalent Ca(1), one Cr(3), and two equivalent Cr(5) atoms to form distorted OCa2Cr3 square pyramids that share  a cornercorner with one O(7)Cr6 octahedra, corners with two equivalent O(3)CaCr5 octahedra, corners with two equivalent O(6)CaCr5 octahedra, corners with two equivalent O(4)Ca2Cr3 square pyramids, corners with four equivalent O(2)Ca2Cr2 tetrahedra, edges with two equivalent O(7)Cr6 octahedra, edges with three equivalent O(6)CaCr5 octahedra,  an edgeedge with one O(4)Ca2Cr3 square pyramid, edges with two equivalent O(5)Ca2Cr3 square pyramids, and  an edgeedge with one O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 8-42°. In the sixth O site, O(6) is bonded to one Ca(1), one Cr(1), two equivalent Cr(3), and two equivalent Cr(5) atoms to form distorted OCaCr5 octahedra that share  a cornercorner with one O(3)CaCr5 octahedra,  a cornercorner with one O(6)CaCr5 octahedra, corners with two equivalent O(7)Cr6 octahedra, corners with two equivalent O(4)Ca2Cr3 square pyramids, corners with two equivalent O(5)Ca2Cr3 square pyramids, edges with two equivalent O(6)CaCr5 octahedra, edges with five equivalent O(7)Cr6 octahedra, edges with three equivalent O(5)Ca2Cr3 square pyramids, and edges with two equivalent O(2)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 0-55°. In the seventh O site, O(7) is bonded to one Cr(5), two equivalent Cr(1), and three equivalent Cr(3) atoms to form OCr6 octahedra that share corners with two equivalent O(6)CaCr5 octahedra, corners with two equivalent O(7)Cr6 octahedra,  a cornercorner with one O(5)Ca2Cr3 square pyramid,  a cornercorner with one O(2)Ca2Cr2 tetrahedra, edges with five equivalent O(6)CaCr5 octahedra, edges with five equivalent O(7)Cr6 octahedra, and edges with two equivalent O(5)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. is represented by the CIF file [CIF]
data_Ca2Cr9O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.122
_cell_length_b   5.372
_cell_length_c   16.627
_cell_angle_alpha   81.388
_cell_angle_beta   85.249
_cell_angle_gamma   75.741
_symmetry_Int_Tables_number   1
_cell_volume   266.876
_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  0.752  0.234  0.230  1.0
  Ca  Ca1  1  0.248  0.766  0.770  1.0
  Cr  Cr2  1  0.500  0.500  0.500  1.0
  Cr  Cr3  1  0.353  0.258  0.040  1.0
  Cr  Cr4  1  0.647  0.742  0.960  1.0
  Cr  Cr5  1  0.247  0.095  0.421  1.0
  Cr  Cr6  1  0.753  0.905  0.579  1.0
  Cr  Cr7  1  0.046  0.772  0.122  1.0
  Cr  Cr8  1  0.954  0.228  0.878  1.0
  Cr  Cr9  1  0.994  0.677  0.338  1.0
  Cr  Cr10  1  0.006  0.323  0.662  1.0
  O  O11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.102  0.557  0.230  1.0
  O  O13  1  0.898  0.443  0.770  1.0
  O  O14  1  0.661  0.547  0.079  1.0
  O  O15  1  0.339  0.453  0.921  1.0
  O  O16  1  0.420  0.014  0.144  1.0
  O  O17  1  0.580  0.986  0.856  1.0
  O  O18  1  0.384  0.936  0.316  1.0
  O  O19  1  0.616  0.064  0.684  1.0
  O  O20  1  0.564  0.415  0.379  1.0
  O  O21  1  0.436  0.585  0.621  1.0
  O  O22  1  0.949  0.791  0.461  1.0
  O  O23  1  0.051  0.209  0.539  1.0
[/CIF]
.