The material structure described by Ba2Cr3AlO7 crystallizes in the orthorhombic Pmmm space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing CrO5 square pyramids. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Al(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Cr(2) atoms to form a mixture of distorted face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Cr(1), and one Cr(2) atom to form a mixture of face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. is represented by the CIF file [CIF]
data_Ba2AlCr3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.826
_cell_length_b   3.968
_cell_length_c   11.577
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   175.773
_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
  Ba  Ba0  1  0.500  0.500  0.315  1.0
  Ba  Ba1  1  0.500  0.500  0.685  1.0
  Al  Al2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.000  0.000  0.139  1.0
  Cr  Cr4  1  0.000  0.000  0.861  1.0
  Cr  Cr5  1  0.000  0.000  0.500  1.0
  O  O6  1  0.000  0.500  0.500  1.0
  O  O7  1  0.500  0.000  0.107  1.0
  O  O8  1  0.500  0.000  0.893  1.0
  O  O9  1  0.000  0.500  0.107  1.0
  O  O10  1  0.000  0.500  0.893  1.0
  O  O11  1  0.000  0.000  0.320  1.0
  O  O12  1  0.000  0.000  0.680  1.0
[/CIF]
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The material structure described by Ba2Cr3AlO7 crystallizes in the orthorhombic Pmmm space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing CrO5 square pyramids. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Al(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Cr(2) atoms to form a mixture of distorted face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Cr(1), and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Cr(1), and one Cr(2) atom to form a mixture of face, edge, and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. is represented by the CIF file [CIF]
data_Ba2AlCr3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.826
_cell_length_b   3.968
_cell_length_c   11.577
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   175.773
_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
  Ba  Ba0  1  0.500  0.500  0.315  1.0
  Ba  Ba1  1  0.500  0.500  0.685  1.0
  Al  Al2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.000  0.000  0.139  1.0
  Cr  Cr4  1  0.000  0.000  0.861  1.0
  Cr  Cr5  1  0.000  0.000  0.500  1.0
  O  O6  1  0.000  0.500  0.500  1.0
  O  O7  1  0.500  0.000  0.107  1.0
  O  O8  1  0.500  0.000  0.893  1.0
  O  O9  1  0.000  0.500  0.107  1.0
  O  O10  1  0.000  0.500  0.893  1.0
  O  O11  1  0.000  0.000  0.320  1.0
  O  O12  1  0.000  0.000  0.680  1.0
[/CIF]
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