The material structure described by U3Ni4Si4 crystallizes in the orthorhombic Immm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to four equivalent Ni(2) and eight equivalent Si(1) atoms to form a mixture of face and edge-sharing USi8Ni4 cuboctahedra. In the second U site, U(2) is bonded in a 14-coordinate geometry to four equivalent Ni(1), four equivalent Ni(2), two equivalent Si(1), and four equivalent Si(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to four equivalent U(2), four equivalent Ni(1), and four equivalent Si(2) atoms to form a mixture of distorted face and corner-sharing NiU4Si4Ni4 cuboctahedra. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to two equivalent U(1), four equivalent U(2), one Si(2), and two equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent U(2), four equivalent U(1), two equivalent Ni(2), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent U(2), one Ni(2), and four equivalent Ni(1) atoms. is represented by the CIF card [CIF]
data_U3(SiNi)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.073
_cell_length_b   12.073
_cell_length_c   12.073
_cell_angle_alpha   161.674
_cell_angle_beta   161.229
_cell_angle_gamma   26.351
_symmetry_Int_Tables_number   1
_cell_volume   177.972
_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
  U  U1  1  0.354  0.854  0.500  1.0
  U  U2  1  0.646  0.146  0.500  1.0
  Si  Si3  1  0.450  0.450  0.000  1.0
  Si  Si4  1  0.550  0.550  0.000  1.0
  Si  Si5  1  0.197  0.697  0.500  1.0
  Si  Si6  1  0.803  0.303  0.500  1.0
  Ni  Ni7  1  0.750  0.750  0.000  1.0
  Ni  Ni8  1  0.901  0.401  0.500  1.0
  Ni  Ni9  1  0.099  0.599  0.500  1.0
  Ni  Ni10  1  0.250  0.250  0.000  1.0
[/CIF]
.
The material structure described by U3Ni4Si4 crystallizes in the orthorhombic Immm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to four equivalent Ni(2) and eight equivalent Si(1) atoms to form a mixture of face and edge-sharing USi8Ni4 cuboctahedra. In the second U site, U(2) is bonded in a 14-coordinate geometry to four equivalent Ni(1), four equivalent Ni(2), two equivalent Si(1), and four equivalent Si(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to four equivalent U(2), four equivalent Ni(1), and four equivalent Si(2) atoms to form a mixture of distorted face and corner-sharing NiU4Si4Ni4 cuboctahedra. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to two equivalent U(1), four equivalent U(2), one Si(2), and two equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent U(2), four equivalent U(1), two equivalent Ni(2), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent U(2), one Ni(2), and four equivalent Ni(1) atoms. is represented by the CIF card [CIF]
data_U3(SiNi)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.073
_cell_length_b   12.073
_cell_length_c   12.073
_cell_angle_alpha   161.674
_cell_angle_beta   161.229
_cell_angle_gamma   26.351
_symmetry_Int_Tables_number   1
_cell_volume   177.972
_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
  U  U1  1  0.354  0.854  0.500  1.0
  U  U2  1  0.646  0.146  0.500  1.0
  Si  Si3  1  0.450  0.450  0.000  1.0
  Si  Si4  1  0.550  0.550  0.000  1.0
  Si  Si5  1  0.197  0.697  0.500  1.0
  Si  Si6  1  0.803  0.303  0.500  1.0
  Ni  Ni7  1  0.750  0.750  0.000  1.0
  Ni  Ni8  1  0.901  0.401  0.500  1.0
  Ni  Ni9  1  0.099  0.599  0.500  1.0
  Ni  Ni10  1  0.250  0.250  0.000  1.0
[/CIF]
.