The material structure described by BaCr4AlO7 crystallizes in the hexagonal P6_3mc space group. Ba(1) is bonded to six equivalent O(1) and six equivalent O(3) atoms to form distorted BaO12 cuboctahedra that share corners with twelve equivalent Ba(1)O12 cuboctahedra, edges with nine equivalent Cr(1)O4 tetrahedra, edges with three equivalent Cr(2)O4 trigonal pyramids, and faces with four equivalent Al(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra, corners with four equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 trigonal pyramids, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 44-51°. In the second Cr site, Cr(2) is bonded to one O(2) and three equivalent O(1) atoms to form CrO4 trigonal pyramids that share corners with three equivalent Al(1)O6 octahedra, corners with six equivalent Cr(1)O4 tetrahedra, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 48°. Al(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form AlO6 octahedra that share corners with nine equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 trigonal pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Cr(1), one Cr(2), and one Al(1) atom. In the second O site, O(2) is bonded in a distorted tetrahedral geometry to one Cr(2) and three equivalent Cr(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and one Al(1) atom. is represented by the CIF card [CIF]
data_BaAlCr4O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.107
_cell_length_b   6.107
_cell_length_c   10.472
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   338.277
_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
  Ba  Ba0  1  0.667  0.333  0.489  1.0
  Ba  Ba1  1  0.333  0.667  0.989  1.0
  Al  Al2  1  0.667  0.333  0.870  1.0
  Al  Al3  1  0.333  0.667  0.370  1.0
  Cr  Cr4  1  0.838  0.162  0.187  1.0
  Cr  Cr5  1  0.676  0.838  0.687  1.0
  Cr  Cr6  1  0.162  0.324  0.687  1.0
  Cr  Cr7  1  0.838  0.676  0.187  1.0
  Cr  Cr8  1  0.324  0.162  0.187  1.0
  Cr  Cr9  1  0.162  0.838  0.687  1.0
  Cr  Cr10  1  0.000  0.000  0.462  1.0
  Cr  Cr11  1  0.000  0.000  0.962  1.0
  O  O12  1  0.815  0.185  0.992  1.0
  O  O13  1  0.629  0.815  0.492  1.0
  O  O14  1  0.185  0.371  0.492  1.0
  O  O15  1  0.815  0.629  0.992  1.0
  O  O16  1  0.371  0.185  0.992  1.0
  O  O17  1  0.185  0.815  0.492  1.0
  O  O18  1  0.000  0.000  0.780  1.0
  O  O19  1  0.000  0.000  0.280  1.0
  O  O20  1  0.488  0.512  0.265  1.0
  O  O21  1  0.975  0.488  0.765  1.0
  O  O22  1  0.512  0.025  0.765  1.0
  O  O23  1  0.488  0.975  0.265  1.0
  O  O24  1  0.512  0.488  0.765  1.0
  O  O25  1  0.025  0.512  0.265  1.0
[/CIF]
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The material structure described by BaCr4AlO7 crystallizes in the hexagonal P6_3mc space group. Ba(1) is bonded to six equivalent O(1) and six equivalent O(3) atoms to form distorted BaO12 cuboctahedra that share corners with twelve equivalent Ba(1)O12 cuboctahedra, edges with nine equivalent Cr(1)O4 tetrahedra, edges with three equivalent Cr(2)O4 trigonal pyramids, and faces with four equivalent Al(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra, corners with four equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 trigonal pyramids, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 44-51°. In the second Cr site, Cr(2) is bonded to one O(2) and three equivalent O(1) atoms to form CrO4 trigonal pyramids that share corners with three equivalent Al(1)O6 octahedra, corners with six equivalent Cr(1)O4 tetrahedra, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 48°. Al(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form AlO6 octahedra that share corners with nine equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 trigonal pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Cr(1), one Cr(2), and one Al(1) atom. In the second O site, O(2) is bonded in a distorted tetrahedral geometry to one Cr(2) and three equivalent Cr(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and one Al(1) atom. is represented by the CIF card [CIF]
data_BaAlCr4O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.107
_cell_length_b   6.107
_cell_length_c   10.472
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   338.277
_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
  Ba  Ba0  1  0.667  0.333  0.489  1.0
  Ba  Ba1  1  0.333  0.667  0.989  1.0
  Al  Al2  1  0.667  0.333  0.870  1.0
  Al  Al3  1  0.333  0.667  0.370  1.0
  Cr  Cr4  1  0.838  0.162  0.187  1.0
  Cr  Cr5  1  0.676  0.838  0.687  1.0
  Cr  Cr6  1  0.162  0.324  0.687  1.0
  Cr  Cr7  1  0.838  0.676  0.187  1.0
  Cr  Cr8  1  0.324  0.162  0.187  1.0
  Cr  Cr9  1  0.162  0.838  0.687  1.0
  Cr  Cr10  1  0.000  0.000  0.462  1.0
  Cr  Cr11  1  0.000  0.000  0.962  1.0
  O  O12  1  0.815  0.185  0.992  1.0
  O  O13  1  0.629  0.815  0.492  1.0
  O  O14  1  0.185  0.371  0.492  1.0
  O  O15  1  0.815  0.629  0.992  1.0
  O  O16  1  0.371  0.185  0.992  1.0
  O  O17  1  0.185  0.815  0.492  1.0
  O  O18  1  0.000  0.000  0.780  1.0
  O  O19  1  0.000  0.000  0.280  1.0
  O  O20  1  0.488  0.512  0.265  1.0
  O  O21  1  0.975  0.488  0.765  1.0
  O  O22  1  0.512  0.025  0.765  1.0
  O  O23  1  0.488  0.975  0.265  1.0
  O  O24  1  0.512  0.488  0.765  1.0
  O  O25  1  0.025  0.512  0.265  1.0
[/CIF]
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