The material described by CaCr4O6 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), 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 0-7°. In the second Cr site, Cr(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Cr(2) and four equivalent Cr(1) atoms to form OCr6 octahedra that share corners with four equivalent O(3)CaCr5 octahedra, corners with two equivalent O(4)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with six equivalent O(3)CaCr5 octahedra, and edges with four equivalent O(2)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cr(1), and two equivalent Cr(2) atoms to form distorted OCa2Cr3 square pyramids that share corners with five equivalent O(3)CaCr5 octahedra, corners with two equivalent O(2)Ca2Cr3 square pyramids, corners with four equivalent O(4)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with three equivalent O(3)CaCr5 octahedra, edges with three equivalent O(2)Ca2Cr3 square pyramids, and  an edgeedge with one O(4)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 9-41°. In the third O site, O(3) is bonded to one Ca(1), two equivalent Cr(2), and three equivalent Cr(1) atoms to form distorted OCaCr5 octahedra that share  a cornercorner with one O(3)CaCr5 octahedra, corners with two equivalent O(1)Cr6 octahedra, corners with five equivalent O(2)Ca2Cr3 square pyramids, edges with three equivalent O(1)Cr6 octahedra, edges with four equivalent O(3)CaCr5 octahedra, edges with three equivalent O(2)Ca2Cr3 square pyramids, and edges with two equivalent O(4)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 3-55°. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Cr(2) atoms to form distorted OCa2Cr2 tetrahedra that share corners with two equivalent O(1)Cr6 octahedra, corners with eight equivalent O(2)Ca2Cr3 square pyramids, corners with two equivalent O(4)Ca2Cr2 tetrahedra, edges with four equivalent O(3)CaCr5 octahedra, and edges with two equivalent O(2)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles are 2°. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaCr4O6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.403
_cell_length_b   5.403
_cell_length_c   15.144
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   146.607
_symmetry_Int_Tables_number   1
_cell_volume   243.291
_cell_formula_units_Z   2
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  0.337  0.663  0.750  1.0
  Ca  Ca1  1  0.663  0.337  0.250  1.0
  Cr  Cr2  1  0.137  0.863  0.043  1.0
  Cr  Cr3  1  0.589  0.411  0.633  1.0
  Cr  Cr4  1  0.863  0.137  0.957  1.0
  Cr  Cr5  1  0.411  0.589  0.367  1.0
  Cr  Cr6  1  0.137  0.863  0.457  1.0
  Cr  Cr7  1  0.863  0.137  0.543  1.0
  Cr  Cr8  1  0.411  0.589  0.133  1.0
  Cr  Cr9  1  0.589  0.411  0.867  1.0
  O  O10  1  0.500  0.500  0.500  1.0
  O  O11  1  0.500  0.500  0.000  1.0
  O  O12  1  0.963  0.037  0.843  1.0
  O  O13  1  0.037  0.963  0.157  1.0
  O  O14  1  0.037  0.963  0.343  1.0
  O  O15  1  0.963  0.037  0.657  1.0
  O  O16  1  0.211  0.789  0.914  1.0
  O  O17  1  0.789  0.211  0.086  1.0
  O  O18  1  0.789  0.211  0.414  1.0
  O  O19  1  0.211  0.789  0.586  1.0
  O  O20  1  0.674  0.326  0.750  1.0
  O  O21  1  0.326  0.674  0.250  1.0
[/CIF]
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The material described by CaCr4O6 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), 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 0-7°. In the second Cr site, Cr(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Cr(2) and four equivalent Cr(1) atoms to form OCr6 octahedra that share corners with four equivalent O(3)CaCr5 octahedra, corners with two equivalent O(4)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with six equivalent O(3)CaCr5 octahedra, and edges with four equivalent O(2)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cr(1), and two equivalent Cr(2) atoms to form distorted OCa2Cr3 square pyramids that share corners with five equivalent O(3)CaCr5 octahedra, corners with two equivalent O(2)Ca2Cr3 square pyramids, corners with four equivalent O(4)Ca2Cr2 tetrahedra, edges with two equivalent O(1)Cr6 octahedra, edges with three equivalent O(3)CaCr5 octahedra, edges with three equivalent O(2)Ca2Cr3 square pyramids, and  an edgeedge with one O(4)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 9-41°. In the third O site, O(3) is bonded to one Ca(1), two equivalent Cr(2), and three equivalent Cr(1) atoms to form distorted OCaCr5 octahedra that share  a cornercorner with one O(3)CaCr5 octahedra, corners with two equivalent O(1)Cr6 octahedra, corners with five equivalent O(2)Ca2Cr3 square pyramids, edges with three equivalent O(1)Cr6 octahedra, edges with four equivalent O(3)CaCr5 octahedra, edges with three equivalent O(2)Ca2Cr3 square pyramids, and edges with two equivalent O(4)Ca2Cr2 tetrahedra. The corner-sharing octahedral tilt angles range from 3-55°. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Cr(2) atoms to form distorted OCa2Cr2 tetrahedra that share corners with two equivalent O(1)Cr6 octahedra, corners with eight equivalent O(2)Ca2Cr3 square pyramids, corners with two equivalent O(4)Ca2Cr2 tetrahedra, edges with four equivalent O(3)CaCr5 octahedra, and edges with two equivalent O(2)Ca2Cr3 square pyramids. The corner-sharing octahedral tilt angles are 2°. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaCr4O6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.403
_cell_length_b   5.403
_cell_length_c   15.144
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   146.607
_symmetry_Int_Tables_number   1
_cell_volume   243.291
_cell_formula_units_Z   2
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  0.337  0.663  0.750  1.0
  Ca  Ca1  1  0.663  0.337  0.250  1.0
  Cr  Cr2  1  0.137  0.863  0.043  1.0
  Cr  Cr3  1  0.589  0.411  0.633  1.0
  Cr  Cr4  1  0.863  0.137  0.957  1.0
  Cr  Cr5  1  0.411  0.589  0.367  1.0
  Cr  Cr6  1  0.137  0.863  0.457  1.0
  Cr  Cr7  1  0.863  0.137  0.543  1.0
  Cr  Cr8  1  0.411  0.589  0.133  1.0
  Cr  Cr9  1  0.589  0.411  0.867  1.0
  O  O10  1  0.500  0.500  0.500  1.0
  O  O11  1  0.500  0.500  0.000  1.0
  O  O12  1  0.963  0.037  0.843  1.0
  O  O13  1  0.037  0.963  0.157  1.0
  O  O14  1  0.037  0.963  0.343  1.0
  O  O15  1  0.963  0.037  0.657  1.0
  O  O16  1  0.211  0.789  0.914  1.0
  O  O17  1  0.789  0.211  0.086  1.0
  O  O18  1  0.789  0.211  0.414  1.0
  O  O19  1  0.211  0.789  0.586  1.0
  O  O20  1  0.674  0.326  0.750  1.0
  O  O21  1  0.326  0.674  0.250  1.0
[/CIF]
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