The structure described by Hf(Nb)Si crystallizes in the orthorhombic Amm2 space group. There are six inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); three equivalent Nb(1); four equivalent Nb(2); one Si(3); two equivalent Si(1); and two equivalent Si(2) atoms. In the second Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); two equivalent Nb(2); three equivalent Nb(1); one Si(1); two equivalent Si(3); and four equivalent Si(2) atoms. In the third Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2), three equivalent Hf(1), two equivalent Nb(2), three equivalent Nb(1), one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the fourth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); three equivalent Nb(1); four equivalent Nb(2); one Si(3); two equivalent Si(1); and two equivalent Si(2) atoms. In the fifth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); three equivalent Nb(1); four equivalent Nb(2); one Si(3); two equivalent Si(1); and two equivalent Si(2) atoms. In the sixth Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); two equivalent Nb(2); three equivalent Nb(1); one Si(1); two equivalent Si(3); and four equivalent Si(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 12-coordinate geometry to three Hf(1,1); three Hf(2,2); two equivalent Nb(2); one Si(1); one Si(3); and two equivalent Si(2) atoms. In the second Nb site, Nb(2) is bonded to two Hf(2,2); four Hf(1,1,1); two equivalent Nb(1); two equivalent Nb(2); and two equivalent Si(1) atoms to form distorted NbHf6Nb4Si2 cuboctahedra that share corners with four equivalent Nb(2)Hf6Nb4Si2 cuboctahedra, edges with two equivalent Nb(2)Hf6Nb4Si2 cuboctahedra, faces with four equivalent Nb(2)Hf6Nb4Si2 cuboctahedra, and faces with four equivalent Si(1)Hf6Nb6 cuboctahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to two Hf(2,2); four Hf(1,1); two equivalent Nb(1); and four equivalent Nb(2) atoms to form SiHf6Nb6 cuboctahedra that share corners with four equivalent Si(1)Hf6Nb6 cuboctahedra, edges with two equivalent Si(1)Hf6Nb6 cuboctahedra, and faces with eight equivalent Nb(2)Hf6Nb4Si2 cuboctahedra. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two Hf(1,1); four Hf(2,2,2); two equivalent Nb(1); one Si(2); and one Si(3) atom. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to two Hf(1,1); four Hf(2,2); two equivalent Nb(1); and two equivalent Si(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_HfNbSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.449
_cell_length_b   5.449
_cell_length_c   8.376
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   60.855
_symmetry_Int_Tables_number   1
_cell_volume   217.194
_cell_formula_units_Z   4
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  0.333  0.333  0.552  1.0
  Hf  Hf1  1  0.663  0.663  0.438  1.0
  Hf  Hf2  1  0.663  0.663  0.062  1.0
  Hf  Hf3  1  0.333  0.333  0.948  1.0
  Nb  Nb4  1  0.000  0.000  0.476  1.0
  Nb  Nb5  1  0.000  0.000  0.024  1.0
  Nb  Nb6  1  0.832  0.338  0.750  1.0
  Nb  Nb7  1  0.338  0.832  0.750  1.0
  Si  Si8  1  0.834  0.834  0.750  1.0
  Si  Si9  1  0.188  0.630  0.250  1.0
  Si  Si10  1  0.630  0.188  0.250  1.0
  Si  Si11  1  0.187  0.187  0.250  1.0
[/CIF]
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The structure described by Hf(Nb)Si crystallizes in the orthorhombic Amm2 space group. There are six inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); three equivalent Nb(1); four equivalent Nb(2); one Si(3); two equivalent Si(1); and two equivalent Si(2) atoms. In the second Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); two equivalent Nb(2); three equivalent Nb(1); one Si(1); two equivalent Si(3); and four equivalent Si(2) atoms. In the third Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2), three equivalent Hf(1), two equivalent Nb(2), three equivalent Nb(1), one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the fourth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); three equivalent Nb(1); four equivalent Nb(2); one Si(3); two equivalent Si(1); and two equivalent Si(2) atoms. In the fifth Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(1); three Hf(2,2); three equivalent Nb(1); four equivalent Nb(2); one Si(3); two equivalent Si(1); and two equivalent Si(2) atoms. In the sixth Hf site, Hf(2) is bonded in a 16-coordinate geometry to one Hf(2); three Hf(1,1); two equivalent Nb(2); three equivalent Nb(1); one Si(1); two equivalent Si(3); and four equivalent Si(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 12-coordinate geometry to three Hf(1,1); three Hf(2,2); two equivalent Nb(2); one Si(1); one Si(3); and two equivalent Si(2) atoms. In the second Nb site, Nb(2) is bonded to two Hf(2,2); four Hf(1,1,1); two equivalent Nb(1); two equivalent Nb(2); and two equivalent Si(1) atoms to form distorted NbHf6Nb4Si2 cuboctahedra that share corners with four equivalent Nb(2)Hf6Nb4Si2 cuboctahedra, edges with two equivalent Nb(2)Hf6Nb4Si2 cuboctahedra, faces with four equivalent Nb(2)Hf6Nb4Si2 cuboctahedra, and faces with four equivalent Si(1)Hf6Nb6 cuboctahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to two Hf(2,2); four Hf(1,1); two equivalent Nb(1); and four equivalent Nb(2) atoms to form SiHf6Nb6 cuboctahedra that share corners with four equivalent Si(1)Hf6Nb6 cuboctahedra, edges with two equivalent Si(1)Hf6Nb6 cuboctahedra, and faces with eight equivalent Nb(2)Hf6Nb4Si2 cuboctahedra. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two Hf(1,1); four Hf(2,2,2); two equivalent Nb(1); one Si(2); and one Si(3) atom. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to two Hf(1,1); four Hf(2,2); two equivalent Nb(1); and two equivalent Si(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_HfNbSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.449
_cell_length_b   5.449
_cell_length_c   8.376
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   60.855
_symmetry_Int_Tables_number   1
_cell_volume   217.194
_cell_formula_units_Z   4
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  0.333  0.333  0.552  1.0
  Hf  Hf1  1  0.663  0.663  0.438  1.0
  Hf  Hf2  1  0.663  0.663  0.062  1.0
  Hf  Hf3  1  0.333  0.333  0.948  1.0
  Nb  Nb4  1  0.000  0.000  0.476  1.0
  Nb  Nb5  1  0.000  0.000  0.024  1.0
  Nb  Nb6  1  0.832  0.338  0.750  1.0
  Nb  Nb7  1  0.338  0.832  0.750  1.0
  Si  Si8  1  0.834  0.834  0.750  1.0
  Si  Si9  1  0.188  0.630  0.250  1.0
  Si  Si10  1  0.630  0.188  0.250  1.0
  Si  Si11  1  0.187  0.187  0.250  1.0
[/CIF]
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