The material described by BaCuO2 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form corner-sharing CuO4 trigonal pyramids. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form corner-sharing CuO4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, corner, and face-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 56°. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, corner, and face-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 56°. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), and two equivalent Cu(2) atoms. is represented by the CIF file [CIF]
data_BaCuO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.061
_cell_length_b   11.910
_cell_length_c   3.703
_cell_angle_alpha   90.000
_cell_angle_beta   90.009
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   267.304
_cell_formula_units_Z   4
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  0.981  0.893  0.501  1.0
  Ba  Ba1  1  0.519  0.608  0.497  1.0
  Ba  Ba2  1  0.481  0.108  0.503  1.0
  Ba  Ba3  1  0.019  0.393  0.499  1.0
  Cu  Cu4  1  0.984  0.124  0.006  1.0
  Cu  Cu5  1  0.515  0.377  0.003  1.0
  Cu  Cu6  1  0.485  0.877  0.997  1.0
  Cu  Cu7  1  0.016  0.624  0.994  1.0
  O  O8  1  0.989  0.665  0.494  1.0
  O  O9  1  0.011  0.165  0.506  1.0
  O  O10  1  0.259  0.511  0.997  1.0
  O  O11  1  0.242  0.989  0.002  1.0
  O  O12  1  0.511  0.836  0.497  1.0
  O  O13  1  0.489  0.336  0.503  1.0
  O  O14  1  0.758  0.489  0.998  1.0
  O  O15  1  0.741  0.011  0.003  1.0
[/CIF]
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The material described by BaCuO2 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form corner-sharing CuO4 trigonal pyramids. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form corner-sharing CuO4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, corner, and face-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 56°. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, corner, and face-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 56°. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), and two equivalent Cu(2) atoms. is represented by the CIF file [CIF]
data_BaCuO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.061
_cell_length_b   11.910
_cell_length_c   3.703
_cell_angle_alpha   90.000
_cell_angle_beta   90.009
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   267.304
_cell_formula_units_Z   4
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  0.981  0.893  0.501  1.0
  Ba  Ba1  1  0.519  0.608  0.497  1.0
  Ba  Ba2  1  0.481  0.108  0.503  1.0
  Ba  Ba3  1  0.019  0.393  0.499  1.0
  Cu  Cu4  1  0.984  0.124  0.006  1.0
  Cu  Cu5  1  0.515  0.377  0.003  1.0
  Cu  Cu6  1  0.485  0.877  0.997  1.0
  Cu  Cu7  1  0.016  0.624  0.994  1.0
  O  O8  1  0.989  0.665  0.494  1.0
  O  O9  1  0.011  0.165  0.506  1.0
  O  O10  1  0.259  0.511  0.997  1.0
  O  O11  1  0.242  0.989  0.002  1.0
  O  O12  1  0.511  0.836  0.497  1.0
  O  O13  1  0.489  0.336  0.503  1.0
  O  O14  1  0.758  0.489  0.998  1.0
  O  O15  1  0.741  0.011  0.003  1.0
[/CIF]
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