The material structure described by HfFeSi2 crystallizes in the orthorhombic Immm space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 12-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), one Si(2), one Si(5), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to four equivalent Fe(2), one Si(2), two equivalent Si(1), two equivalent Si(4), and two equivalent Si(5) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to four equivalent Hf(1), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Fe site, Fe(2) is bonded to two equivalent Hf(1), two equivalent Hf(2), two equivalent Fe(2), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(5) atoms to form a mixture of distorted corner, edge, and face-sharing FeHf4Fe2Si6 cuboctahedra. There are five inequivalent Si sites. In the first Si site, Si(4) is bonded in a 10-coordinate geometry to two equivalent Hf(2), four equivalent Hf(1), two equivalent Fe(1), and two equivalent Si(4) atoms. In the second Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent Hf(1), two equivalent Hf(2), and four equivalent Fe(2) atoms. In the third Si site, Si(1) is bonded in a 7-coordinate geometry to one Hf(2), two equivalent Hf(1), one Fe(1), two equivalent Fe(2), and one Si(1) atom. In the fourth Si site, Si(2) is bonded in a 7-coordinate geometry to one Hf(2), two equivalent Hf(1), and four equivalent Fe(2) atoms. In the fifth Si site, Si(3) is bonded in a 7-coordinate geometry to four equivalent Hf(1), two equivalent Fe(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_HfFeSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.595
_cell_length_b   9.595
_cell_length_c   9.595
_cell_angle_alpha   149.154
_cell_angle_beta   132.970
_cell_angle_gamma   57.305
_symmetry_Int_Tables_number   1
_cell_volume   329.025
_cell_formula_units_Z   6
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
  Hf  Hf0  1  0.859  0.596  0.263  1.0
  Hf  Hf1  1  0.141  0.404  0.737  1.0
  Hf  Hf2  1  0.666  0.404  0.263  1.0
  Hf  Hf3  1  0.334  0.596  0.737  1.0
  Hf  Hf4  1  0.142  0.142  1.000  1.0
  Hf  Hf5  1  0.858  0.858  0.000  1.0
  Fe  Fe6  1  0.745  0.000  0.745  1.0
  Fe  Fe7  1  0.000  0.000  0.500  1.0
  Fe  Fe8  1  0.500  0.500  0.500  1.0
  Fe  Fe9  1  0.500  0.000  0.000  1.0
  Fe  Fe10  1  0.255  1.000  0.255  1.0
  Fe  Fe11  1  0.000  0.500  1.000  1.0
  Si  Si12  1  0.489  0.140  0.349  1.0
  Si  Si13  1  0.511  0.860  0.651  1.0
  Si  Si14  1  0.209  0.860  0.349  1.0
  Si  Si15  1  0.791  0.140  0.651  1.0
  Si  Si16  1  0.702  0.702  1.000  1.0
  Si  Si17  1  0.298  0.298  0.000  1.0
  Si  Si18  1  0.500  0.743  0.243  1.0
  Si  Si19  1  0.500  0.257  0.757  1.0
  Si  Si20  1  0.000  0.253  0.253  1.0
  Si  Si21  1  0.216  0.716  0.500  1.0
  Si  Si22  1  1.000  0.747  0.747  1.0
  Si  Si23  1  0.784  0.284  0.500  1.0
[/CIF]
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The material structure described by HfFeSi2 crystallizes in the orthorhombic Immm space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 12-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), one Si(2), one Si(5), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to four equivalent Fe(2), one Si(2), two equivalent Si(1), two equivalent Si(4), and two equivalent Si(5) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to four equivalent Hf(1), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Fe site, Fe(2) is bonded to two equivalent Hf(1), two equivalent Hf(2), two equivalent Fe(2), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(5) atoms to form a mixture of distorted corner, edge, and face-sharing FeHf4Fe2Si6 cuboctahedra. There are five inequivalent Si sites. In the first Si site, Si(4) is bonded in a 10-coordinate geometry to two equivalent Hf(2), four equivalent Hf(1), two equivalent Fe(1), and two equivalent Si(4) atoms. In the second Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent Hf(1), two equivalent Hf(2), and four equivalent Fe(2) atoms. In the third Si site, Si(1) is bonded in a 7-coordinate geometry to one Hf(2), two equivalent Hf(1), one Fe(1), two equivalent Fe(2), and one Si(1) atom. In the fourth Si site, Si(2) is bonded in a 7-coordinate geometry to one Hf(2), two equivalent Hf(1), and four equivalent Fe(2) atoms. In the fifth Si site, Si(3) is bonded in a 7-coordinate geometry to four equivalent Hf(1), two equivalent Fe(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_HfFeSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.595
_cell_length_b   9.595
_cell_length_c   9.595
_cell_angle_alpha   149.154
_cell_angle_beta   132.970
_cell_angle_gamma   57.305
_symmetry_Int_Tables_number   1
_cell_volume   329.025
_cell_formula_units_Z   6
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
  Hf  Hf0  1  0.859  0.596  0.263  1.0
  Hf  Hf1  1  0.141  0.404  0.737  1.0
  Hf  Hf2  1  0.666  0.404  0.263  1.0
  Hf  Hf3  1  0.334  0.596  0.737  1.0
  Hf  Hf4  1  0.142  0.142  1.000  1.0
  Hf  Hf5  1  0.858  0.858  0.000  1.0
  Fe  Fe6  1  0.745  0.000  0.745  1.0
  Fe  Fe7  1  0.000  0.000  0.500  1.0
  Fe  Fe8  1  0.500  0.500  0.500  1.0
  Fe  Fe9  1  0.500  0.000  0.000  1.0
  Fe  Fe10  1  0.255  1.000  0.255  1.0
  Fe  Fe11  1  0.000  0.500  1.000  1.0
  Si  Si12  1  0.489  0.140  0.349  1.0
  Si  Si13  1  0.511  0.860  0.651  1.0
  Si  Si14  1  0.209  0.860  0.349  1.0
  Si  Si15  1  0.791  0.140  0.651  1.0
  Si  Si16  1  0.702  0.702  1.000  1.0
  Si  Si17  1  0.298  0.298  0.000  1.0
  Si  Si18  1  0.500  0.743  0.243  1.0
  Si  Si19  1  0.500  0.257  0.757  1.0
  Si  Si20  1  0.000  0.253  0.253  1.0
  Si  Si21  1  0.216  0.716  0.500  1.0
  Si  Si22  1  1.000  0.747  0.747  1.0
  Si  Si23  1  0.784  0.284  0.500  1.0
[/CIF]
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