The structure described by BaCuSi2O6 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded in a 12-coordinate geometry to four equivalent O(1) and eight equivalent O(2) atoms. Cu(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(2) atoms. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(1), one Cu(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaCu(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.558
_cell_length_b   7.558
_cell_length_c   7.558
_cell_angle_alpha   123.231
_cell_angle_beta   123.231
_cell_angle_gamma   84.490
_symmetry_Int_Tables_number   1
_cell_volume   288.963
_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  0.250  0.750  0.500  1.0
  Ba  Ba1  1  0.750  0.250  0.500  1.0
  Cu  Cu2  1  0.121  0.121  0.000  1.0
  Cu  Cu3  1  0.879  0.879  0.000  1.0
  Si  Si4  1  0.726  0.274  0.000  1.0
  Si  Si5  1  0.274  0.274  0.548  1.0
  Si  Si6  1  0.274  0.726  0.000  1.0
  Si  Si7  1  0.726  0.726  0.452  1.0
  O  O8  1  0.500  0.235  0.735  1.0
  O  O9  1  0.682  0.067  0.000  1.0
  O  O10  1  0.067  0.067  0.385  1.0
  O  O11  1  0.235  0.500  0.735  1.0
  O  O12  1  0.318  0.933  0.000  1.0
  O  O13  1  0.500  0.765  0.265  1.0
  O  O14  1  0.765  0.500  0.265  1.0
  O  O15  1  0.067  0.682  0.000  1.0
  O  O16  1  0.318  0.318  0.385  1.0
  O  O17  1  0.933  0.933  0.615  1.0
  O  O18  1  0.933  0.318  0.000  1.0
  O  O19  1  0.682  0.682  0.615  1.0
[/CIF]
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The structure described by BaCuSi2O6 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded in a 12-coordinate geometry to four equivalent O(1) and eight equivalent O(2) atoms. Cu(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(2) atoms. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(1), one Cu(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaCu(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.558
_cell_length_b   7.558
_cell_length_c   7.558
_cell_angle_alpha   123.231
_cell_angle_beta   123.231
_cell_angle_gamma   84.490
_symmetry_Int_Tables_number   1
_cell_volume   288.963
_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  0.250  0.750  0.500  1.0
  Ba  Ba1  1  0.750  0.250  0.500  1.0
  Cu  Cu2  1  0.121  0.121  0.000  1.0
  Cu  Cu3  1  0.879  0.879  0.000  1.0
  Si  Si4  1  0.726  0.274  0.000  1.0
  Si  Si5  1  0.274  0.274  0.548  1.0
  Si  Si6  1  0.274  0.726  0.000  1.0
  Si  Si7  1  0.726  0.726  0.452  1.0
  O  O8  1  0.500  0.235  0.735  1.0
  O  O9  1  0.682  0.067  0.000  1.0
  O  O10  1  0.067  0.067  0.385  1.0
  O  O11  1  0.235  0.500  0.735  1.0
  O  O12  1  0.318  0.933  0.000  1.0
  O  O13  1  0.500  0.765  0.265  1.0
  O  O14  1  0.765  0.500  0.265  1.0
  O  O15  1  0.067  0.682  0.000  1.0
  O  O16  1  0.318  0.318  0.385  1.0
  O  O17  1  0.933  0.933  0.615  1.0
  O  O18  1  0.933  0.318  0.000  1.0
  O  O19  1  0.682  0.682  0.615  1.0
[/CIF]
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