The material described by HfCuSi2 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal P4/nmm space group. Hf(1) is bonded to four equivalent Cu(1), four equivalent Si(1), and four equivalent Si(2) atoms to form distorted HfCu4Si8 cuboctahedra that share corners with four equivalent Hf(1)Cu4Si8 cuboctahedra, edges with eight equivalent Hf(1)Cu4Si8 cuboctahedra, edges with eight equivalent Cu(1)Hf4Cu4Si4 cuboctahedra, faces with four equivalent Hf(1)Cu4Si8 cuboctahedra, and faces with four equivalent Cu(1)Hf4Cu4Si4 cuboctahedra. Cu(1) is bonded to four equivalent Hf(1), four equivalent Cu(1), and four equivalent Si(2) atoms to form CuHf4Cu4Si4 cuboctahedra that share corners with four equivalent Cu(1)Hf4Cu4Si4 cuboctahedra, edges with eight equivalent Hf(1)Cu4Si8 cuboctahedra, faces with four equivalent Hf(1)Cu4Si8 cuboctahedra, and faces with eight equivalent Cu(1)Hf4Cu4Si4 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to four equivalent Hf(1) and four equivalent Si(1) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to four equivalent Hf(1) and four equivalent Cu(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_HfCuSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.661
_cell_length_b   3.661
_cell_length_c   8.964
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   120.162
_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
  Hf  Hf0  1  0.750  0.750  0.266  1.0
  Hf  Hf1  1  0.250  0.250  0.734  1.0
  Cu  Cu2  1  0.750  0.250  0.000  1.0
  Cu  Cu3  1  0.250  0.750  0.000  1.0
  Si  Si4  1  0.250  0.750  0.500  1.0
  Si  Si5  1  0.750  0.250  0.500  1.0
  Si  Si6  1  0.250  0.250  0.170  1.0
  Si  Si7  1  0.750  0.750  0.830  1.0
[/CIF]
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The material described by HfCuSi2 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal P4/nmm space group. Hf(1) is bonded to four equivalent Cu(1), four equivalent Si(1), and four equivalent Si(2) atoms to form distorted HfCu4Si8 cuboctahedra that share corners with four equivalent Hf(1)Cu4Si8 cuboctahedra, edges with eight equivalent Hf(1)Cu4Si8 cuboctahedra, edges with eight equivalent Cu(1)Hf4Cu4Si4 cuboctahedra, faces with four equivalent Hf(1)Cu4Si8 cuboctahedra, and faces with four equivalent Cu(1)Hf4Cu4Si4 cuboctahedra. Cu(1) is bonded to four equivalent Hf(1), four equivalent Cu(1), and four equivalent Si(2) atoms to form CuHf4Cu4Si4 cuboctahedra that share corners with four equivalent Cu(1)Hf4Cu4Si4 cuboctahedra, edges with eight equivalent Hf(1)Cu4Si8 cuboctahedra, faces with four equivalent Hf(1)Cu4Si8 cuboctahedra, and faces with eight equivalent Cu(1)Hf4Cu4Si4 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to four equivalent Hf(1) and four equivalent Si(1) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to four equivalent Hf(1) and four equivalent Cu(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_HfCuSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.661
_cell_length_b   3.661
_cell_length_c   8.964
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   120.162
_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
  Hf  Hf0  1  0.750  0.750  0.266  1.0
  Hf  Hf1  1  0.250  0.250  0.734  1.0
  Cu  Cu2  1  0.750  0.250  0.000  1.0
  Cu  Cu3  1  0.250  0.750  0.000  1.0
  Si  Si4  1  0.250  0.750  0.500  1.0
  Si  Si5  1  0.750  0.250  0.500  1.0
  Si  Si6  1  0.250  0.250  0.170  1.0
  Si  Si7  1  0.750  0.750  0.830  1.0
[/CIF]
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