The crystal structure described by Cu3Nb2O8 crystallizes in the triclinic P-1 space group. Nb(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form distorted edge-sharing CuO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Nb(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing ONbCu3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(1), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Nb(1) and one Cu(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Nb(1) and one Cu(2) atom. is represented by the CIF file [CIF]
data_Nb2Cu3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.259
_cell_length_b   5.526
_cell_length_c   6.214
_cell_angle_alpha   73.526
_cell_angle_beta   81.791
_cell_angle_gamma   66.661
_symmetry_Int_Tables_number   1
_cell_volume   158.906
_cell_formula_units_Z   1
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
  Nb  Nb0  1  0.782  0.458  0.346  1.0
  Nb  Nb1  1  0.218  0.542  0.654  1.0
  Cu  Cu2  1  0.000  1.000  0.000  1.0
  Cu  Cu3  1  0.536  0.933  0.754  1.0
  Cu  Cu4  1  0.464  0.067  0.246  1.0
  O  O5  1  0.761  0.800  0.107  1.0
  O  O6  1  0.239  0.200  0.893  1.0
  O  O7  1  0.737  0.254  0.167  1.0
  O  O8  1  0.263  0.746  0.833  1.0
  O  O9  1  0.631  0.263  0.624  1.0
  O  O10  1  0.369  0.737  0.376  1.0
  O  O11  1  0.830  0.686  0.601  1.0
  O  O12  1  0.170  0.314  0.399  1.0
[/CIF]
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The crystal structure described by Cu3Nb2O8 crystallizes in the triclinic P-1 space group. Nb(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form distorted edge-sharing CuO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Nb(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing ONbCu3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(1), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Nb(1) and one Cu(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Nb(1) and one Cu(2) atom. is represented by the CIF file [CIF]
data_Nb2Cu3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.259
_cell_length_b   5.526
_cell_length_c   6.214
_cell_angle_alpha   73.526
_cell_angle_beta   81.791
_cell_angle_gamma   66.661
_symmetry_Int_Tables_number   1
_cell_volume   158.906
_cell_formula_units_Z   1
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
  Nb  Nb0  1  0.782  0.458  0.346  1.0
  Nb  Nb1  1  0.218  0.542  0.654  1.0
  Cu  Cu2  1  0.000  1.000  0.000  1.0
  Cu  Cu3  1  0.536  0.933  0.754  1.0
  Cu  Cu4  1  0.464  0.067  0.246  1.0
  O  O5  1  0.761  0.800  0.107  1.0
  O  O6  1  0.239  0.200  0.893  1.0
  O  O7  1  0.737  0.254  0.167  1.0
  O  O8  1  0.263  0.746  0.833  1.0
  O  O9  1  0.631  0.263  0.624  1.0
  O  O10  1  0.369  0.737  0.376  1.0
  O  O11  1  0.830  0.686  0.601  1.0
  O  O12  1  0.170  0.314  0.399  1.0
[/CIF]
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