The material described by BaCu2V2O8 crystallizes in the tetragonal I-42d space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with four equivalent V(1)O4 tetrahedra, edges with four equivalent V(2)O4 tetrahedra, and faces with four equivalent Cu(1)O5 square pyramids. In the second Ba site, Ba(2) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(2), and four equivalent O(4) atoms. There are two inequivalent V sites. In the first V site, V(1) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form VO4 tetrahedra that share corners with two equivalent Ba(1)O12 cuboctahedra and corners with six equivalent Cu(1)O5 square pyramids. In the second V site, V(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form VO4 tetrahedra that share corners with four equivalent Cu(1)O5 square pyramids and edges with two equivalent Ba(1)O12 cuboctahedra. Cu(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form distorted CuO5 square pyramids that share corners with two equivalent V(2)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra,  an edgeedge with one Cu(1)O5 square pyramid, and  a faceface with one Ba(1)O12 cuboctahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one V(2), and one Cu(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), one V(1), and one Cu(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one V(2), and one Cu(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(2), one V(1), and two equivalent Cu(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaV2(CuO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.133
_cell_length_b   10.133
_cell_length_c   10.133
_cell_angle_alpha   99.440
_cell_angle_beta   99.440
_cell_angle_gamma   132.218
_symmetry_Int_Tables_number   1
_cell_volume   704.423
_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
  Ba  Ba0  1  0.500  0.500  0.000  1.0
  Ba  Ba1  1  0.000  0.000  0.000  1.0
  Ba  Ba2  1  0.750  0.250  0.500  1.0
  Ba  Ba3  1  0.250  0.750  0.500  1.0
  V  V4  1  0.025  0.375  0.150  1.0
  V  V5  1  0.125  0.975  0.350  1.0
  V  V6  1  0.625  0.326  0.201  1.0
  V  V7  1  0.674  0.875  0.299  1.0
  V  V8  1  0.125  0.424  0.799  1.0
  V  V9  1  0.576  0.375  0.701  1.0
  V  V10  1  0.625  0.775  0.650  1.0
  V  V11  1  0.225  0.875  0.850  1.0
  Cu  Cu12  1  0.331  0.851  0.167  1.0
  Cu  Cu13  1  0.101  0.081  0.667  1.0
  Cu  Cu14  1  0.149  0.316  0.480  1.0
  Cu  Cu15  1  0.919  0.586  0.020  1.0
  Cu  Cu16  1  0.566  0.899  0.980  1.0
  Cu  Cu17  1  0.836  0.669  0.520  1.0
  Cu  Cu18  1  0.414  0.434  0.333  1.0
  Cu  Cu19  1  0.684  0.164  0.833  1.0
  O  O20  1  0.552  0.183  0.685  1.0
  O  O21  1  0.058  0.696  0.685  1.0
  O  O22  1  0.817  0.502  0.369  1.0
  O  O23  1  0.623  0.762  0.815  1.0
  O  O24  1  0.498  0.867  0.315  1.0
  O  O25  1  0.329  0.637  0.941  1.0
  O  O26  1  0.133  0.448  0.631  1.0
  O  O27  1  0.554  0.113  0.192  1.0
  O  O28  1  0.198  0.195  0.352  1.0
  O  O29  1  0.805  0.157  0.003  1.0
  O  O30  1  0.638  0.446  0.559  1.0
  O  O31  1  0.012  0.373  0.315  1.0
  O  O32  1  0.887  0.079  0.441  1.0
  O  O33  1  0.407  0.555  0.503  1.0
  O  O34  1  0.192  0.377  0.139  1.0
  O  O35  1  0.612  0.671  0.308  1.0
  O  O36  1  0.445  0.948  0.852  1.0
  O  O37  1  0.238  0.054  0.861  1.0
  O  O38  1  0.363  0.304  0.692  1.0
  O  O39  1  0.052  0.904  0.497  1.0
  O  O40  1  0.154  0.802  0.997  1.0
  O  O41  1  0.921  0.362  0.808  1.0
  O  O42  1  0.696  0.388  0.059  1.0
  O  O43  1  0.843  0.846  0.648  1.0
  O  O44  1  0.946  0.808  0.185  1.0
  O  O45  1  0.304  0.988  0.361  1.0
  O  O46  1  0.433  0.302  0.185  1.0
  O  O47  1  0.096  0.593  0.148  1.0
  O  O48  1  0.627  0.942  0.639  1.0
  O  O49  1  0.117  0.248  0.815  1.0
  O  O50  1  0.752  0.567  0.869  1.0
  O  O51  1  0.698  0.883  0.131  1.0
[/CIF]
.
The material described by BaCu2V2O8 crystallizes in the tetragonal I-42d space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with four equivalent V(1)O4 tetrahedra, edges with four equivalent V(2)O4 tetrahedra, and faces with four equivalent Cu(1)O5 square pyramids. In the second Ba site, Ba(2) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(2), and four equivalent O(4) atoms. There are two inequivalent V sites. In the first V site, V(1) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form VO4 tetrahedra that share corners with two equivalent Ba(1)O12 cuboctahedra and corners with six equivalent Cu(1)O5 square pyramids. In the second V site, V(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form VO4 tetrahedra that share corners with four equivalent Cu(1)O5 square pyramids and edges with two equivalent Ba(1)O12 cuboctahedra. Cu(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form distorted CuO5 square pyramids that share corners with two equivalent V(2)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra,  an edgeedge with one Cu(1)O5 square pyramid, and  a faceface with one Ba(1)O12 cuboctahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one V(2), and one Cu(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), one V(1), and one Cu(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one V(2), and one Cu(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(2), one V(1), and two equivalent Cu(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaV2(CuO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.133
_cell_length_b   10.133
_cell_length_c   10.133
_cell_angle_alpha   99.440
_cell_angle_beta   99.440
_cell_angle_gamma   132.218
_symmetry_Int_Tables_number   1
_cell_volume   704.423
_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
  Ba  Ba0  1  0.500  0.500  0.000  1.0
  Ba  Ba1  1  0.000  0.000  0.000  1.0
  Ba  Ba2  1  0.750  0.250  0.500  1.0
  Ba  Ba3  1  0.250  0.750  0.500  1.0
  V  V4  1  0.025  0.375  0.150  1.0
  V  V5  1  0.125  0.975  0.350  1.0
  V  V6  1  0.625  0.326  0.201  1.0
  V  V7  1  0.674  0.875  0.299  1.0
  V  V8  1  0.125  0.424  0.799  1.0
  V  V9  1  0.576  0.375  0.701  1.0
  V  V10  1  0.625  0.775  0.650  1.0
  V  V11  1  0.225  0.875  0.850  1.0
  Cu  Cu12  1  0.331  0.851  0.167  1.0
  Cu  Cu13  1  0.101  0.081  0.667  1.0
  Cu  Cu14  1  0.149  0.316  0.480  1.0
  Cu  Cu15  1  0.919  0.586  0.020  1.0
  Cu  Cu16  1  0.566  0.899  0.980  1.0
  Cu  Cu17  1  0.836  0.669  0.520  1.0
  Cu  Cu18  1  0.414  0.434  0.333  1.0
  Cu  Cu19  1  0.684  0.164  0.833  1.0
  O  O20  1  0.552  0.183  0.685  1.0
  O  O21  1  0.058  0.696  0.685  1.0
  O  O22  1  0.817  0.502  0.369  1.0
  O  O23  1  0.623  0.762  0.815  1.0
  O  O24  1  0.498  0.867  0.315  1.0
  O  O25  1  0.329  0.637  0.941  1.0
  O  O26  1  0.133  0.448  0.631  1.0
  O  O27  1  0.554  0.113  0.192  1.0
  O  O28  1  0.198  0.195  0.352  1.0
  O  O29  1  0.805  0.157  0.003  1.0
  O  O30  1  0.638  0.446  0.559  1.0
  O  O31  1  0.012  0.373  0.315  1.0
  O  O32  1  0.887  0.079  0.441  1.0
  O  O33  1  0.407  0.555  0.503  1.0
  O  O34  1  0.192  0.377  0.139  1.0
  O  O35  1  0.612  0.671  0.308  1.0
  O  O36  1  0.445  0.948  0.852  1.0
  O  O37  1  0.238  0.054  0.861  1.0
  O  O38  1  0.363  0.304  0.692  1.0
  O  O39  1  0.052  0.904  0.497  1.0
  O  O40  1  0.154  0.802  0.997  1.0
  O  O41  1  0.921  0.362  0.808  1.0
  O  O42  1  0.696  0.388  0.059  1.0
  O  O43  1  0.843  0.846  0.648  1.0
  O  O44  1  0.946  0.808  0.185  1.0
  O  O45  1  0.304  0.988  0.361  1.0
  O  O46  1  0.433  0.302  0.185  1.0
  O  O47  1  0.096  0.593  0.148  1.0
  O  O48  1  0.627  0.942  0.639  1.0
  O  O49  1  0.117  0.248  0.815  1.0
  O  O50  1  0.752  0.567  0.869  1.0
  O  O51  1  0.698  0.883  0.131  1.0
[/CIF]
.