The material structure described by U2Nb3Si4 crystallizes in the tetragonal P4_12_12 space group. U(1) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent Si(2) and four equivalent Si(1) atoms to form distorted corner-sharing NbSi6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent U(1), two equivalent Nb(1), three equivalent Nb(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent U(1), one Nb(1), three equivalent Nb(2), and one Si(1) atom. is represented by the CIF card [CIF]
data_U2Nb3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.054
_cell_length_b   7.054
_cell_length_c   12.997
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   646.724
_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
  U  U0  1  0.995  0.333  0.219  1.0
  U  U1  1  0.005  0.667  0.719  1.0
  U  U2  1  0.167  0.495  0.469  1.0
  U  U3  1  0.505  0.833  0.031  1.0
  U  U4  1  0.833  0.505  0.969  1.0
  U  U5  1  0.495  0.167  0.531  1.0
  U  U6  1  0.333  0.995  0.781  1.0
  U  U7  1  0.667  0.005  0.281  1.0
  Nb  Nb8  1  0.168  0.168  0.000  1.0
  Nb  Nb9  1  0.832  0.832  0.500  1.0
  Nb  Nb10  1  0.332  0.668  0.250  1.0
  Nb  Nb11  1  0.668  0.332  0.750  1.0
  Nb  Nb12  1  0.157  0.999  0.375  1.0
  Nb  Nb13  1  0.843  0.001  0.875  1.0
  Nb  Nb14  1  0.501  0.657  0.625  1.0
  Nb  Nb15  1  0.343  0.499  0.875  1.0
  Nb  Nb16  1  0.499  0.343  0.125  1.0
  Nb  Nb17  1  0.657  0.501  0.375  1.0
  Nb  Nb18  1  0.999  0.157  0.625  1.0
  Nb  Nb19  1  0.001  0.843  0.125  1.0
  Si  Si20  1  0.295  0.040  0.185  1.0
  Si  Si21  1  0.705  0.960  0.685  1.0
  Si  Si22  1  0.460  0.795  0.435  1.0
  Si  Si23  1  0.205  0.540  0.065  1.0
  Si  Si24  1  0.540  0.205  0.935  1.0
  Si  Si25  1  0.795  0.460  0.565  1.0
  Si  Si26  1  0.040  0.295  0.815  1.0
  Si  Si27  1  0.960  0.705  0.315  1.0
  Si  Si28  1  0.371  0.293  0.317  1.0
  Si  Si29  1  0.629  0.707  0.817  1.0
  Si  Si30  1  0.207  0.871  0.567  1.0
  Si  Si31  1  0.129  0.793  0.933  1.0
  Si  Si32  1  0.793  0.129  0.067  1.0
  Si  Si33  1  0.871  0.207  0.433  1.0
  Si  Si34  1  0.293  0.371  0.683  1.0
  Si  Si35  1  0.707  0.629  0.183  1.0
[/CIF]
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The material structure described by U2Nb3Si4 crystallizes in the tetragonal P4_12_12 space group. U(1) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent Si(2) and four equivalent Si(1) atoms to form distorted corner-sharing NbSi6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent U(1), two equivalent Nb(1), three equivalent Nb(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent U(1), one Nb(1), three equivalent Nb(2), and one Si(1) atom. is represented by the CIF card [CIF]
data_U2Nb3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.054
_cell_length_b   7.054
_cell_length_c   12.997
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   646.724
_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
  U  U0  1  0.995  0.333  0.219  1.0
  U  U1  1  0.005  0.667  0.719  1.0
  U  U2  1  0.167  0.495  0.469  1.0
  U  U3  1  0.505  0.833  0.031  1.0
  U  U4  1  0.833  0.505  0.969  1.0
  U  U5  1  0.495  0.167  0.531  1.0
  U  U6  1  0.333  0.995  0.781  1.0
  U  U7  1  0.667  0.005  0.281  1.0
  Nb  Nb8  1  0.168  0.168  0.000  1.0
  Nb  Nb9  1  0.832  0.832  0.500  1.0
  Nb  Nb10  1  0.332  0.668  0.250  1.0
  Nb  Nb11  1  0.668  0.332  0.750  1.0
  Nb  Nb12  1  0.157  0.999  0.375  1.0
  Nb  Nb13  1  0.843  0.001  0.875  1.0
  Nb  Nb14  1  0.501  0.657  0.625  1.0
  Nb  Nb15  1  0.343  0.499  0.875  1.0
  Nb  Nb16  1  0.499  0.343  0.125  1.0
  Nb  Nb17  1  0.657  0.501  0.375  1.0
  Nb  Nb18  1  0.999  0.157  0.625  1.0
  Nb  Nb19  1  0.001  0.843  0.125  1.0
  Si  Si20  1  0.295  0.040  0.185  1.0
  Si  Si21  1  0.705  0.960  0.685  1.0
  Si  Si22  1  0.460  0.795  0.435  1.0
  Si  Si23  1  0.205  0.540  0.065  1.0
  Si  Si24  1  0.540  0.205  0.935  1.0
  Si  Si25  1  0.795  0.460  0.565  1.0
  Si  Si26  1  0.040  0.295  0.815  1.0
  Si  Si27  1  0.960  0.705  0.315  1.0
  Si  Si28  1  0.371  0.293  0.317  1.0
  Si  Si29  1  0.629  0.707  0.817  1.0
  Si  Si30  1  0.207  0.871  0.567  1.0
  Si  Si31  1  0.129  0.793  0.933  1.0
  Si  Si32  1  0.793  0.129  0.067  1.0
  Si  Si33  1  0.871  0.207  0.433  1.0
  Si  Si34  1  0.293  0.371  0.683  1.0
  Si  Si35  1  0.707  0.629  0.183  1.0
[/CIF]
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