The structure described by U3Si crystallizes in the tetragonal I4/mcm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 12-coordinate geometry to eight equivalent U(2) and four equivalent Si(1) atoms. In the second U site, U(2) is bonded in a 12-coordinate geometry to four equivalent U(1), four equivalent U(2), and four equivalent Si(1) atoms. Si(1) is bonded to four equivalent U(1) and eight equivalent U(2) atoms to form a mixture of corner and face-sharing SiU12 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_U3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.009
_cell_length_b   6.009
_cell_length_c   6.003
_cell_angle_alpha   120.354
_cell_angle_beta   120.354
_cell_angle_gamma   89.424
_symmetry_Int_Tables_number   1
_cell_volume   152.417
_cell_formula_units_Z   2
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  0.750  0.250  0.500  1.0
  U  U1  1  0.250  0.750  0.500  1.0
  U  U2  1  0.221  0.721  0.943  1.0
  U  U3  1  0.779  0.279  0.057  1.0
  U  U4  1  0.722  0.778  0.500  1.0
  U  U5  1  0.278  0.222  0.500  1.0
  Si  Si6  1  0.750  0.750  1.000  1.0
  Si  Si7  1  0.250  0.250  1.000  1.0
[/CIF]
.
The structure described by U3Si crystallizes in the tetragonal I4/mcm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 12-coordinate geometry to eight equivalent U(2) and four equivalent Si(1) atoms. In the second U site, U(2) is bonded in a 12-coordinate geometry to four equivalent U(1), four equivalent U(2), and four equivalent Si(1) atoms. Si(1) is bonded to four equivalent U(1) and eight equivalent U(2) atoms to form a mixture of corner and face-sharing SiU12 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_U3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.009
_cell_length_b   6.009
_cell_length_c   6.003
_cell_angle_alpha   120.354
_cell_angle_beta   120.354
_cell_angle_gamma   89.424
_symmetry_Int_Tables_number   1
_cell_volume   152.417
_cell_formula_units_Z   2
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  0.750  0.250  0.500  1.0
  U  U1  1  0.250  0.750  0.500  1.0
  U  U2  1  0.221  0.721  0.943  1.0
  U  U3  1  0.779  0.279  0.057  1.0
  U  U4  1  0.722  0.778  0.500  1.0
  U  U5  1  0.278  0.222  0.500  1.0
  Si  Si6  1  0.750  0.750  1.000  1.0
  Si  Si7  1  0.250  0.250  1.000  1.0
[/CIF]
.