The material structure described by U3Fe2Si7 crystallizes in the orthorhombic Cmmm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to four equivalent Si(2), four equivalent Si(3), and four equivalent Si(4) atoms to form a mixture of distorted corner and face-sharing USi12 cuboctahedra. In the second U site, U(2) is bonded in a 14-coordinate geometry to four equivalent Fe(1), two equivalent Si(2), two equivalent Si(3), and six equivalent Si(1) atoms. Fe(1) is bonded in a 5-coordinate geometry to four equivalent U(2), one Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent U(2), one Fe(1), and two equivalent Si(1) atoms. In the second Si site, Si(2) is bonded in a 2-coordinate geometry to two equivalent U(1), two equivalent U(2), and two equivalent Fe(1) atoms. In the third Si site, Si(3) is bonded in a 2-coordinate geometry to two equivalent U(1), two equivalent U(2), and two equivalent Fe(1) atoms. In the fourth Si site, Si(4) is bonded in a square co-planar geometry to four equivalent U(1) atoms. is represented by the CIF file [CIF]
data_U3Fe2Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.512
_cell_length_b   12.512
_cell_length_c   3.988
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   161.611
_symmetry_Int_Tables_number   1
_cell_volume   196.962
_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  0.500  1.0
  U  U1  1  0.317  0.683  0.000  1.0
  U  U2  1  0.683  0.317  0.000  1.0
  Fe  Fe3  1  0.128  0.872  0.500  1.0
  Fe  Fe4  1  0.872  0.128  0.500  1.0
  Si  Si5  1  0.221  0.779  0.500  1.0
  Si  Si6  1  0.779  0.221  0.500  1.0
  Si  Si7  1  0.086  0.914  0.000  1.0
  Si  Si8  1  0.914  0.086  0.000  1.0
  Si  Si9  1  0.414  0.586  0.500  1.0
  Si  Si10  1  0.500  0.500  0.000  1.0
  Si  Si11  1  0.586  0.414  0.500  1.0
[/CIF]
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The material structure described by U3Fe2Si7 crystallizes in the orthorhombic Cmmm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to four equivalent Si(2), four equivalent Si(3), and four equivalent Si(4) atoms to form a mixture of distorted corner and face-sharing USi12 cuboctahedra. In the second U site, U(2) is bonded in a 14-coordinate geometry to four equivalent Fe(1), two equivalent Si(2), two equivalent Si(3), and six equivalent Si(1) atoms. Fe(1) is bonded in a 5-coordinate geometry to four equivalent U(2), one Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent U(2), one Fe(1), and two equivalent Si(1) atoms. In the second Si site, Si(2) is bonded in a 2-coordinate geometry to two equivalent U(1), two equivalent U(2), and two equivalent Fe(1) atoms. In the third Si site, Si(3) is bonded in a 2-coordinate geometry to two equivalent U(1), two equivalent U(2), and two equivalent Fe(1) atoms. In the fourth Si site, Si(4) is bonded in a square co-planar geometry to four equivalent U(1) atoms. is represented by the CIF file [CIF]
data_U3Fe2Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.512
_cell_length_b   12.512
_cell_length_c   3.988
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   161.611
_symmetry_Int_Tables_number   1
_cell_volume   196.962
_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  0.500  1.0
  U  U1  1  0.317  0.683  0.000  1.0
  U  U2  1  0.683  0.317  0.000  1.0
  Fe  Fe3  1  0.128  0.872  0.500  1.0
  Fe  Fe4  1  0.872  0.128  0.500  1.0
  Si  Si5  1  0.221  0.779  0.500  1.0
  Si  Si6  1  0.779  0.221  0.500  1.0
  Si  Si7  1  0.086  0.914  0.000  1.0
  Si  Si8  1  0.914  0.086  0.000  1.0
  Si  Si9  1  0.414  0.586  0.500  1.0
  Si  Si10  1  0.500  0.500  0.000  1.0
  Si  Si11  1  0.586  0.414  0.500  1.0
[/CIF]
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