The compound described by Cu4O(PO4)2 crystallizes in the triclinic P-1 space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Cu(2)O5 trigonal bipyramid. In the second Cu site, Cu(2) is bonded to one O(2), one O(5), one O(7), one O(8), and one O(9) atom to form CuO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. In the third Cu site, Cu(3) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. In the fourth Cu site, Cu(4) is bonded in a rectangular see-saw-like geometry to one O(3), one O(5), one O(6), and one O(9) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 trigonal bipyramids and corners with two equivalent Cu(2)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 trigonal bipyramids and corners with two equivalent Cu(2)O5 trigonal bipyramids. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Cu(3) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(2), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(4), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(3), and one P(1) atom. In the fifth O site, O(5) is bonded in a tetrahedral geometry to one Cu(1), one Cu(2), one Cu(3), and one Cu(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cu(3), one Cu(4), and one P(1) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Cu(2), one Cu(3), and one P(1) atom. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one P(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Cu(2), one Cu(4), and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu4P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.262
_cell_length_b   7.534
_cell_length_c   8.010
_cell_angle_alpha   99.323
_cell_angle_beta   112.255
_cell_angle_gamma   97.986
_symmetry_Int_Tables_number   1
_cell_volume   336.738
_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
  Cu  Cu0  1  0.884  0.105  0.758  1.0
  Cu  Cu1  1  0.408  0.125  0.763  1.0
  Cu  Cu2  1  0.116  0.895  0.242  1.0
  Cu  Cu3  1  0.656  0.385  0.589  1.0
  Cu  Cu4  1  0.344  0.615  0.411  1.0
  Cu  Cu5  1  0.592  0.875  0.237  1.0
  Cu  Cu6  1  0.154  0.670  0.937  1.0
  Cu  Cu7  1  0.846  0.330  0.063  1.0
  P  P8  1  1.000  0.784  0.579  1.0
  P  P9  1  0.371  0.264  0.151  1.0
  P  P10  1  0.629  0.736  0.849  1.0
  P  P11  1  0.000  0.216  0.421  1.0
  O  O12  1  0.513  0.584  0.666  1.0
  O  O13  1  0.345  0.073  0.191  1.0
  O  O14  1  0.132  0.300  0.028  1.0
  O  O15  1  0.487  0.416  0.334  1.0
  O  O16  1  0.655  0.927  0.809  1.0
  O  O17  1  0.149  0.780  0.464  1.0
  O  O18  1  0.300  0.727  0.204  1.0
  O  O19  1  0.700  0.273  0.796  1.0
  O  O20  1  0.004  0.622  0.672  1.0
  O  O21  1  0.749  0.796  0.465  1.0
  O  O22  1  0.868  0.700  0.972  1.0
  O  O23  1  0.851  0.220  0.536  1.0
  O  O24  1  0.118  0.966  0.739  1.0
  O  O25  1  0.996  0.378  0.328  1.0
  O  O26  1  0.477  0.726  0.961  1.0
  O  O27  1  0.882  0.034  0.261  1.0
  O  O28  1  0.251  0.204  0.535  1.0
  O  O29  1  0.523  0.274  0.039  1.0
[/CIF]
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The compound described by Cu4O(PO4)2 crystallizes in the triclinic P-1 space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Cu(2)O5 trigonal bipyramid, and  an edgeedge with one Cu(2)O5 trigonal bipyramid. In the second Cu site, Cu(2) is bonded to one O(2), one O(5), one O(7), one O(8), and one O(9) atom to form CuO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Cu(1)O5 trigonal bipyramid, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. In the third Cu site, Cu(3) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. In the fourth Cu site, Cu(4) is bonded in a rectangular see-saw-like geometry to one O(3), one O(5), one O(6), and one O(9) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 trigonal bipyramids and corners with two equivalent Cu(2)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 trigonal bipyramids and corners with two equivalent Cu(2)O5 trigonal bipyramids. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Cu(3) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(2), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(4), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(3), and one P(1) atom. In the fifth O site, O(5) is bonded in a tetrahedral geometry to one Cu(1), one Cu(2), one Cu(3), and one Cu(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cu(3), one Cu(4), and one P(1) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Cu(2), one Cu(3), and one P(1) atom. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one P(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Cu(2), one Cu(4), and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu4P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.262
_cell_length_b   7.534
_cell_length_c   8.010
_cell_angle_alpha   99.323
_cell_angle_beta   112.255
_cell_angle_gamma   97.986
_symmetry_Int_Tables_number   1
_cell_volume   336.738
_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
  Cu  Cu0  1  0.884  0.105  0.758  1.0
  Cu  Cu1  1  0.408  0.125  0.763  1.0
  Cu  Cu2  1  0.116  0.895  0.242  1.0
  Cu  Cu3  1  0.656  0.385  0.589  1.0
  Cu  Cu4  1  0.344  0.615  0.411  1.0
  Cu  Cu5  1  0.592  0.875  0.237  1.0
  Cu  Cu6  1  0.154  0.670  0.937  1.0
  Cu  Cu7  1  0.846  0.330  0.063  1.0
  P  P8  1  1.000  0.784  0.579  1.0
  P  P9  1  0.371  0.264  0.151  1.0
  P  P10  1  0.629  0.736  0.849  1.0
  P  P11  1  0.000  0.216  0.421  1.0
  O  O12  1  0.513  0.584  0.666  1.0
  O  O13  1  0.345  0.073  0.191  1.0
  O  O14  1  0.132  0.300  0.028  1.0
  O  O15  1  0.487  0.416  0.334  1.0
  O  O16  1  0.655  0.927  0.809  1.0
  O  O17  1  0.149  0.780  0.464  1.0
  O  O18  1  0.300  0.727  0.204  1.0
  O  O19  1  0.700  0.273  0.796  1.0
  O  O20  1  0.004  0.622  0.672  1.0
  O  O21  1  0.749  0.796  0.465  1.0
  O  O22  1  0.868  0.700  0.972  1.0
  O  O23  1  0.851  0.220  0.536  1.0
  O  O24  1  0.118  0.966  0.739  1.0
  O  O25  1  0.996  0.378  0.328  1.0
  O  O26  1  0.477  0.726  0.961  1.0
  O  O27  1  0.882  0.034  0.261  1.0
  O  O28  1  0.251  0.204  0.535  1.0
  O  O29  1  0.523  0.274  0.039  1.0
[/CIF]
.