The compound described by UNb6O16 crystallizes in the triclinic P-1 space group. U(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(8) atoms to form UO6 octahedra that share corners with two equivalent Nb(3)O4 tetrahedra. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), and two equivalent O(1) atoms. In the second Nb site, Nb(2) is bonded in a 5-coordinate geometry to one O(4), one O(5), one O(6), and two equivalent O(3) atoms. In the third Nb site, Nb(3) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form NbO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one U(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a water-like geometry to one U(1) and one Nb(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Nb(1) and two equivalent Nb(2) atoms. In the fourth O site, O(4) is bonded in a single-bond geometry to one Nb(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(2) and one Nb(3) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one Nb(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one U(1) and one Nb(3) atom. is represented by the CIF file [CIF]
data_UNb6O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.065
_cell_length_b   6.604
_cell_length_c   9.426
_cell_angle_alpha   100.973
_cell_angle_beta   80.674
_cell_angle_gamma   76.015
_symmetry_Int_Tables_number   1
_cell_volume   466.737
_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
  U  U0  1  0.000  0.000  0.000  1.0
  Nb  Nb1  1  0.994  0.622  0.177  1.0
  Nb  Nb2  1  0.210  0.382  0.478  1.0
  Nb  Nb3  1  0.396  0.077  0.763  1.0
  Nb  Nb4  1  0.604  0.923  0.237  1.0
  Nb  Nb5  1  0.790  0.618  0.522  1.0
  Nb  Nb6  1  0.006  0.378  0.823  1.0
  O  O7  1  0.021  0.332  0.046  1.0
  O  O8  1  0.093  0.850  0.178  1.0
  O  O9  1  0.038  0.481  0.357  1.0
  O  O10  1  0.312  0.585  0.506  1.0
  O  O11  1  0.227  0.230  0.654  1.0
  O  O12  1  0.383  0.129  0.351  1.0
  O  O13  1  0.438  0.293  0.875  1.0
  O  O14  1  0.271  0.943  0.885  1.0
  O  O15  1  0.729  0.057  0.115  1.0
  O  O16  1  0.562  0.707  0.125  1.0
  O  O17  1  0.617  0.871  0.649  1.0
  O  O18  1  0.773  0.770  0.346  1.0
  O  O19  1  0.688  0.415  0.494  1.0
  O  O20  1  0.962  0.519  0.643  1.0
  O  O21  1  0.907  0.150  0.822  1.0
  O  O22  1  0.979  0.668  0.954  1.0
[/CIF]
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The compound described by UNb6O16 crystallizes in the triclinic P-1 space group. U(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(8) atoms to form UO6 octahedra that share corners with two equivalent Nb(3)O4 tetrahedra. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), and two equivalent O(1) atoms. In the second Nb site, Nb(2) is bonded in a 5-coordinate geometry to one O(4), one O(5), one O(6), and two equivalent O(3) atoms. In the third Nb site, Nb(3) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form NbO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one U(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a water-like geometry to one U(1) and one Nb(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Nb(1) and two equivalent Nb(2) atoms. In the fourth O site, O(4) is bonded in a single-bond geometry to one Nb(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(2) and one Nb(3) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one Nb(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one U(1) and one Nb(3) atom. is represented by the CIF file [CIF]
data_UNb6O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.065
_cell_length_b   6.604
_cell_length_c   9.426
_cell_angle_alpha   100.973
_cell_angle_beta   80.674
_cell_angle_gamma   76.015
_symmetry_Int_Tables_number   1
_cell_volume   466.737
_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
  U  U0  1  0.000  0.000  0.000  1.0
  Nb  Nb1  1  0.994  0.622  0.177  1.0
  Nb  Nb2  1  0.210  0.382  0.478  1.0
  Nb  Nb3  1  0.396  0.077  0.763  1.0
  Nb  Nb4  1  0.604  0.923  0.237  1.0
  Nb  Nb5  1  0.790  0.618  0.522  1.0
  Nb  Nb6  1  0.006  0.378  0.823  1.0
  O  O7  1  0.021  0.332  0.046  1.0
  O  O8  1  0.093  0.850  0.178  1.0
  O  O9  1  0.038  0.481  0.357  1.0
  O  O10  1  0.312  0.585  0.506  1.0
  O  O11  1  0.227  0.230  0.654  1.0
  O  O12  1  0.383  0.129  0.351  1.0
  O  O13  1  0.438  0.293  0.875  1.0
  O  O14  1  0.271  0.943  0.885  1.0
  O  O15  1  0.729  0.057  0.115  1.0
  O  O16  1  0.562  0.707  0.125  1.0
  O  O17  1  0.617  0.871  0.649  1.0
  O  O18  1  0.773  0.770  0.346  1.0
  O  O19  1  0.688  0.415  0.494  1.0
  O  O20  1  0.962  0.519  0.643  1.0
  O  O21  1  0.907  0.150  0.822  1.0
  O  O22  1  0.979  0.668  0.954  1.0
[/CIF]
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