The crystal structure described by BaCa(CuO2)4 crystallizes in the trigonal P-31m space group. Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share edges with six equivalent Ba(1)O12 cuboctahedra, edges with twelve equivalent Cu(1)O4 tetrahedra, and faces with two equivalent Ca(1)O6 octahedra. Ca(1) is bonded to six equivalent O(1) atoms to form CaO6 octahedra that share corners with twelve equivalent Cu(1)O4 tetrahedra and faces with two equivalent Ba(1)O12 cuboctahedra. Cu(1) is bonded to one O(2) and three equivalent O(1) atoms to form CuO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra, corners with four equivalent Cu(1)O4 tetrahedra, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 58°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ca(1), and two equivalent Cu(1) atoms to form a mixture of distorted edge and corner-sharing OBaCaCu2 trigonal pyramids. In the second O site, O(2) is bonded in a linear geometry to three equivalent Ba(1) and two equivalent Cu(1) atoms. is represented by the CIF file [CIF]
data_BaCa(CuO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.383
_cell_length_b   5.383
_cell_length_c   7.758
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   194.667
_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  0.000  0.000  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.500  1.0
  Cu  Cu2  1  0.333  0.667  0.761  1.0
  Cu  Cu3  1  0.667  0.333  0.761  1.0
  Cu  Cu4  1  0.333  0.667  0.239  1.0
  Cu  Cu5  1  0.667  0.333  0.239  1.0
  O  O6  1  0.331  0.331  0.701  1.0
  O  O7  1  0.669  0.000  0.701  1.0
  O  O8  1  0.000  0.669  0.701  1.0
  O  O9  1  0.669  0.669  0.299  1.0
  O  O10  1  0.000  0.331  0.299  1.0
  O  O11  1  0.331  0.000  0.299  1.0
  O  O12  1  0.333  0.667  0.000  1.0
  O  O13  1  0.667  0.333  0.000  1.0
[/CIF]
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The crystal structure described by BaCa(CuO2)4 crystallizes in the trigonal P-31m space group. Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share edges with six equivalent Ba(1)O12 cuboctahedra, edges with twelve equivalent Cu(1)O4 tetrahedra, and faces with two equivalent Ca(1)O6 octahedra. Ca(1) is bonded to six equivalent O(1) atoms to form CaO6 octahedra that share corners with twelve equivalent Cu(1)O4 tetrahedra and faces with two equivalent Ba(1)O12 cuboctahedra. Cu(1) is bonded to one O(2) and three equivalent O(1) atoms to form CuO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra, corners with four equivalent Cu(1)O4 tetrahedra, and edges with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 58°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ca(1), and two equivalent Cu(1) atoms to form a mixture of distorted edge and corner-sharing OBaCaCu2 trigonal pyramids. In the second O site, O(2) is bonded in a linear geometry to three equivalent Ba(1) and two equivalent Cu(1) atoms. is represented by the CIF file [CIF]
data_BaCa(CuO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.383
_cell_length_b   5.383
_cell_length_c   7.758
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   194.667
_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  0.000  0.000  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.500  1.0
  Cu  Cu2  1  0.333  0.667  0.761  1.0
  Cu  Cu3  1  0.667  0.333  0.761  1.0
  Cu  Cu4  1  0.333  0.667  0.239  1.0
  Cu  Cu5  1  0.667  0.333  0.239  1.0
  O  O6  1  0.331  0.331  0.701  1.0
  O  O7  1  0.669  0.000  0.701  1.0
  O  O8  1  0.000  0.669  0.701  1.0
  O  O9  1  0.669  0.669  0.299  1.0
  O  O10  1  0.000  0.331  0.299  1.0
  O  O11  1  0.331  0.000  0.299  1.0
  O  O12  1  0.333  0.667  0.000  1.0
  O  O13  1  0.667  0.333  0.000  1.0
[/CIF]
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