The material described by Cu3AsO7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(5), and one O(6) atom. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted CuO5 square pyramids that share corners with two equivalent As(1)O4 tetrahedra and corners with two equivalent Cu(3)O5 trigonal bipyramids. In the third Cu site, Cu(3) is bonded to one O(4), one O(6), one O(7), and two equivalent O(1) atoms to form CuO5 trigonal bipyramids that share corners with two equivalent Cu(2)O5 square pyramids, corners with three equivalent As(1)O4 tetrahedra, and  an edgeedge with one Cu(3)O5 trigonal bipyramid. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share corners with two equivalent Cu(2)O5 square pyramids and corners with three equivalent Cu(3)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 150 degrees geometry to one Cu(1) and one Cu(2) atom. In the second O site, O(6) is bonded in a trigonal planar geometry to one Cu(1), one Cu(2), and one Cu(3) atom. In the third O site, O(7) is bonded in a bent 120 degrees geometry to one Cu(2) and one Cu(3) atom. In the fourth O site, O(1) is bonded in a trigonal planar geometry to two equivalent Cu(3) and one As(1) atom. In the fifth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Cu(1), one Cu(2), and one As(1) atom. In the sixth O site, O(3) is bonded in a trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one As(1) atom. In the seventh O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cu(3) and one As(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu3AsO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.229
_cell_length_b   7.609
_cell_length_c   11.925
_cell_angle_alpha   98.976
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   558.227
_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
  Cu  Cu0  1  0.638  0.197  0.165  1.0
  Cu  Cu1  1  0.138  0.803  0.335  1.0
  Cu  Cu2  1  0.362  0.803  0.835  1.0
  Cu  Cu3  1  0.862  0.197  0.665  1.0
  Cu  Cu4  1  0.883  0.201  0.380  1.0
  Cu  Cu5  1  0.383  0.799  0.120  1.0
  Cu  Cu6  1  0.117  0.799  0.620  1.0
  Cu  Cu7  1  0.617  0.201  0.880  1.0
  Cu  Cu8  1  0.863  0.627  0.092  1.0
  Cu  Cu9  1  0.363  0.373  0.408  1.0
  Cu  Cu10  1  0.137  0.373  0.908  1.0
  Cu  Cu11  1  0.637  0.627  0.592  1.0
  As  As12  1  0.653  0.699  0.323  1.0
  As  As13  1  0.153  0.301  0.177  1.0
  As  As14  1  0.347  0.301  0.677  1.0
  As  As15  1  0.847  0.699  0.823  1.0
  O  O16  1  0.586  0.575  0.428  1.0
  O  O17  1  0.086  0.425  0.072  1.0
  O  O18  1  0.414  0.425  0.572  1.0
  O  O19  1  0.914  0.575  0.928  1.0
  O  O20  1  0.847  0.856  0.363  1.0
  O  O21  1  0.347  0.144  0.137  1.0
  O  O22  1  0.153  0.144  0.637  1.0
  O  O23  1  0.653  0.856  0.863  1.0
  O  O24  1  0.431  0.822  0.285  1.0
  O  O25  1  0.931  0.178  0.215  1.0
  O  O26  1  0.569  0.178  0.715  1.0
  O  O27  1  0.069  0.822  0.785  1.0
  O  O28  1  0.725  0.537  0.213  1.0
  O  O29  1  0.225  0.463  0.287  1.0
  O  O30  1  0.275  0.463  0.787  1.0
  O  O31  1  0.775  0.537  0.713  1.0
  O  O32  1  0.712  0.237  0.023  1.0
  O  O33  1  0.212  0.763  0.477  1.0
  O  O34  1  0.288  0.763  0.977  1.0
  O  O35  1  0.788  0.237  0.523  1.0
  O  O36  1  0.104  0.791  0.177  1.0
  O  O37  1  0.604  0.209  0.323  1.0
  O  O38  1  0.896  0.209  0.823  1.0
  O  O39  1  0.396  0.791  0.677  1.0
  O  O40  1  0.668  0.814  0.098  1.0
  O  O41  1  0.168  0.186  0.402  1.0
  O  O42  1  0.332  0.186  0.902  1.0
  O  O43  1  0.832  0.814  0.598  1.0
[/CIF]
.
The material described by Cu3AsO7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(5), and one O(6) atom. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted CuO5 square pyramids that share corners with two equivalent As(1)O4 tetrahedra and corners with two equivalent Cu(3)O5 trigonal bipyramids. In the third Cu site, Cu(3) is bonded to one O(4), one O(6), one O(7), and two equivalent O(1) atoms to form CuO5 trigonal bipyramids that share corners with two equivalent Cu(2)O5 square pyramids, corners with three equivalent As(1)O4 tetrahedra, and  an edgeedge with one Cu(3)O5 trigonal bipyramid. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share corners with two equivalent Cu(2)O5 square pyramids and corners with three equivalent Cu(3)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 150 degrees geometry to one Cu(1) and one Cu(2) atom. In the second O site, O(6) is bonded in a trigonal planar geometry to one Cu(1), one Cu(2), and one Cu(3) atom. In the third O site, O(7) is bonded in a bent 120 degrees geometry to one Cu(2) and one Cu(3) atom. In the fourth O site, O(1) is bonded in a trigonal planar geometry to two equivalent Cu(3) and one As(1) atom. In the fifth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Cu(1), one Cu(2), and one As(1) atom. In the sixth O site, O(3) is bonded in a trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one As(1) atom. In the seventh O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cu(3) and one As(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu3AsO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.229
_cell_length_b   7.609
_cell_length_c   11.925
_cell_angle_alpha   98.976
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   558.227
_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
  Cu  Cu0  1  0.638  0.197  0.165  1.0
  Cu  Cu1  1  0.138  0.803  0.335  1.0
  Cu  Cu2  1  0.362  0.803  0.835  1.0
  Cu  Cu3  1  0.862  0.197  0.665  1.0
  Cu  Cu4  1  0.883  0.201  0.380  1.0
  Cu  Cu5  1  0.383  0.799  0.120  1.0
  Cu  Cu6  1  0.117  0.799  0.620  1.0
  Cu  Cu7  1  0.617  0.201  0.880  1.0
  Cu  Cu8  1  0.863  0.627  0.092  1.0
  Cu  Cu9  1  0.363  0.373  0.408  1.0
  Cu  Cu10  1  0.137  0.373  0.908  1.0
  Cu  Cu11  1  0.637  0.627  0.592  1.0
  As  As12  1  0.653  0.699  0.323  1.0
  As  As13  1  0.153  0.301  0.177  1.0
  As  As14  1  0.347  0.301  0.677  1.0
  As  As15  1  0.847  0.699  0.823  1.0
  O  O16  1  0.586  0.575  0.428  1.0
  O  O17  1  0.086  0.425  0.072  1.0
  O  O18  1  0.414  0.425  0.572  1.0
  O  O19  1  0.914  0.575  0.928  1.0
  O  O20  1  0.847  0.856  0.363  1.0
  O  O21  1  0.347  0.144  0.137  1.0
  O  O22  1  0.153  0.144  0.637  1.0
  O  O23  1  0.653  0.856  0.863  1.0
  O  O24  1  0.431  0.822  0.285  1.0
  O  O25  1  0.931  0.178  0.215  1.0
  O  O26  1  0.569  0.178  0.715  1.0
  O  O27  1  0.069  0.822  0.785  1.0
  O  O28  1  0.725  0.537  0.213  1.0
  O  O29  1  0.225  0.463  0.287  1.0
  O  O30  1  0.275  0.463  0.787  1.0
  O  O31  1  0.775  0.537  0.713  1.0
  O  O32  1  0.712  0.237  0.023  1.0
  O  O33  1  0.212  0.763  0.477  1.0
  O  O34  1  0.288  0.763  0.977  1.0
  O  O35  1  0.788  0.237  0.523  1.0
  O  O36  1  0.104  0.791  0.177  1.0
  O  O37  1  0.604  0.209  0.323  1.0
  O  O38  1  0.896  0.209  0.823  1.0
  O  O39  1  0.396  0.791  0.677  1.0
  O  O40  1  0.668  0.814  0.098  1.0
  O  O41  1  0.168  0.186  0.402  1.0
  O  O42  1  0.332  0.186  0.902  1.0
  O  O43  1  0.832  0.814  0.598  1.0
[/CIF]
.