The material described by BaCuP2O7 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), two equivalent O(7), and three equivalent O(6) atoms. Cu(1) is bonded to one O(3), one O(5), one O(7), and two equivalent O(1) atoms to form distorted CuO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Cu(1)O5 square pyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(2)O4 tetrahedra. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ba(1), two equivalent Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one Cu(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Cu(1), and one P(2) atom. is represented by the CIF file [CIF]
data_BaCuP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.277
_cell_length_b   7.668
_cell_length_c   7.681
_cell_angle_alpha   103.605
_cell_angle_beta   91.672
_cell_angle_gamma   95.402
_symmetry_Int_Tables_number   1
_cell_volume   300.291
_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  0.193  0.777  0.929  1.0
  Ba  Ba1  1  0.807  0.223  0.071  1.0
  Cu  Cu2  1  0.820  0.356  0.597  1.0
  Cu  Cu3  1  0.180  0.644  0.403  1.0
  P  P4  1  0.713  0.808  0.600  1.0
  P  P5  1  0.287  0.192  0.400  1.0
  P  P6  1  0.689  0.734  0.220  1.0
  P  P7  1  0.311  0.266  0.780  1.0
  O  O8  1  0.907  0.664  0.584  1.0
  O  O9  1  0.093  0.336  0.416  1.0
  O  O10  1  0.787  0.968  0.755  1.0
  O  O11  1  0.213  0.032  0.245  1.0
  O  O12  1  0.437  0.722  0.604  1.0
  O  O13  1  0.563  0.278  0.396  1.0
  O  O14  1  0.728  0.876  0.414  1.0
  O  O15  1  0.272  0.124  0.586  1.0
  O  O16  1  0.574  0.376  0.788  1.0
  O  O17  1  0.426  0.624  0.212  1.0
  O  O18  1  0.299  0.158  0.923  1.0
  O  O19  1  0.701  0.842  0.077  1.0
  O  O20  1  0.090  0.389  0.795  1.0
  O  O21  1  0.910  0.611  0.205  1.0
[/CIF]
.
The material described by BaCuP2O7 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), two equivalent O(7), and three equivalent O(6) atoms. Cu(1) is bonded to one O(3), one O(5), one O(7), and two equivalent O(1) atoms to form distorted CuO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Cu(1)O5 square pyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(2)O4 tetrahedra. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ba(1), two equivalent Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one Cu(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Cu(1), and one P(2) atom. is represented by the CIF file [CIF]
data_BaCuP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.277
_cell_length_b   7.668
_cell_length_c   7.681
_cell_angle_alpha   103.605
_cell_angle_beta   91.672
_cell_angle_gamma   95.402
_symmetry_Int_Tables_number   1
_cell_volume   300.291
_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  0.193  0.777  0.929  1.0
  Ba  Ba1  1  0.807  0.223  0.071  1.0
  Cu  Cu2  1  0.820  0.356  0.597  1.0
  Cu  Cu3  1  0.180  0.644  0.403  1.0
  P  P4  1  0.713  0.808  0.600  1.0
  P  P5  1  0.287  0.192  0.400  1.0
  P  P6  1  0.689  0.734  0.220  1.0
  P  P7  1  0.311  0.266  0.780  1.0
  O  O8  1  0.907  0.664  0.584  1.0
  O  O9  1  0.093  0.336  0.416  1.0
  O  O10  1  0.787  0.968  0.755  1.0
  O  O11  1  0.213  0.032  0.245  1.0
  O  O12  1  0.437  0.722  0.604  1.0
  O  O13  1  0.563  0.278  0.396  1.0
  O  O14  1  0.728  0.876  0.414  1.0
  O  O15  1  0.272  0.124  0.586  1.0
  O  O16  1  0.574  0.376  0.788  1.0
  O  O17  1  0.426  0.624  0.212  1.0
  O  O18  1  0.299  0.158  0.923  1.0
  O  O19  1  0.701  0.842  0.077  1.0
  O  O20  1  0.090  0.389  0.795  1.0
  O  O21  1  0.910  0.611  0.205  1.0
[/CIF]
.