The material described by U2Fe3Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded in a 13-coordinate geometry to one U(1), nine equivalent Fe(1), and three equivalent Si(1) atoms. Fe(1) is bonded to six equivalent U(1), four equivalent Fe(1), and two equivalent Si(1) atoms to form distorted FeU6Fe4Si2 cuboctahedra that share corners with four equivalent Si(1)U6Fe6 cuboctahedra, corners with fourteen equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Fe(1)U6Fe4Si2 cuboctahedra, faces with six equivalent Si(1)U6Fe6 cuboctahedra, and faces with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra. Si(1) is bonded to six equivalent U(1) and six equivalent Fe(1) atoms to form SiU6Fe6 cuboctahedra that share corners with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Si(1)U6Fe6 cuboctahedra, faces with two equivalent Si(1)U6Fe6 cuboctahedra, and faces with eighteen equivalent Fe(1)U6Fe4Si2 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_U2Fe3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.115
_cell_length_b   5.112
_cell_length_c   7.307
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   60.021
_symmetry_Int_Tables_number   1
_cell_volume   165.536
_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  0.334  0.333  0.565  1.0
  U  U1  1  0.666  0.667  0.435  1.0
  U  U2  1  0.666  0.667  0.065  1.0
  U  U3  1  0.334  0.333  0.935  1.0
  Fe  Fe4  1  0.833  0.335  0.750  1.0
  Fe  Fe5  1  0.336  0.832  0.750  1.0
  Fe  Fe6  1  0.833  0.832  0.750  1.0
  Fe  Fe7  1  0.167  0.665  0.250  1.0
  Fe  Fe8  1  0.664  0.168  0.250  1.0
  Fe  Fe9  1  0.167  0.168  0.250  1.0
  Si  Si10  1  1.000  0.000  0.500  1.0
  Si  Si11  1  0.000  0.000  0.000  1.0
[/CIF]
.
The material described by U2Fe3Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded in a 13-coordinate geometry to one U(1), nine equivalent Fe(1), and three equivalent Si(1) atoms. Fe(1) is bonded to six equivalent U(1), four equivalent Fe(1), and two equivalent Si(1) atoms to form distorted FeU6Fe4Si2 cuboctahedra that share corners with four equivalent Si(1)U6Fe6 cuboctahedra, corners with fourteen equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Fe(1)U6Fe4Si2 cuboctahedra, faces with six equivalent Si(1)U6Fe6 cuboctahedra, and faces with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra. Si(1) is bonded to six equivalent U(1) and six equivalent Fe(1) atoms to form SiU6Fe6 cuboctahedra that share corners with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Si(1)U6Fe6 cuboctahedra, faces with two equivalent Si(1)U6Fe6 cuboctahedra, and faces with eighteen equivalent Fe(1)U6Fe4Si2 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_U2Fe3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.115
_cell_length_b   5.112
_cell_length_c   7.307
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   60.021
_symmetry_Int_Tables_number   1
_cell_volume   165.536
_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  0.334  0.333  0.565  1.0
  U  U1  1  0.666  0.667  0.435  1.0
  U  U2  1  0.666  0.667  0.065  1.0
  U  U3  1  0.334  0.333  0.935  1.0
  Fe  Fe4  1  0.833  0.335  0.750  1.0
  Fe  Fe5  1  0.336  0.832  0.750  1.0
  Fe  Fe6  1  0.833  0.832  0.750  1.0
  Fe  Fe7  1  0.167  0.665  0.250  1.0
  Fe  Fe8  1  0.664  0.168  0.250  1.0
  Fe  Fe9  1  0.167  0.168  0.250  1.0
  Si  Si10  1  1.000  0.000  0.500  1.0
  Si  Si11  1  0.000  0.000  0.000  1.0
[/CIF]
.