data_BaHfSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.38
_cell_length_b   3.38
_cell_length_c   8.35
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaHfSi2
_chemical_formula_sum   'Ba1 Hf1 Si2'
_cell_volume   95.47
_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
  Ba  Ba0  1  0.0  0.0  0.8  1.0
  Hf  Hf1  1  0.69  0.69  0.06  1.0
  Si  Si2  1  0.0  0.0  0.29  1.0
  Si  Si3  1  0.69  0.69  0.37  1.0

data_BaHfSi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.78
_cell_length_b   4.78
_cell_length_c   8.35
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BaHfSi2
_chemical_formula_sum   'Ba2 Hf2 Si4'
_cell_volume   190.95
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Ba  Ba0  2  0.0  0.0  0.8  1.0
  Hf  Hf1  2  0.19  0.5  0.06  1.0
  Si  Si2  2  0.0  0.0  0.29  1.0
  Si  Si3  2  0.19  0.5  0.37  1.0

Ba Hf Si Si
BaHfSi2 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a distorted single-bond geometry to three equivalent Hf(1) and one Si(2) atom. There is one shorter (2.60 Å) and two longer (3.34 Å) Ba(1)-Hf(1) bond lengths. The Ba(1)-Si(2) bond length is 3.88 Å. Hf(1) is bonded in a 7-coordinate geometry to three equivalent Ba(1), one Si(2), and three equivalent Si(1) atoms. The Hf(1)-Si(2) bond length is 2.62 Å. There is one shorter (2.40 Å) and two longer (3.19 Å) Hf(1)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 2-coordinate geometry to three equivalent Hf(1) and three equivalent Si(2) atoms. There is one shorter (1.64 Å) and two longer (2.66 Å) Si(1)-Si(2) bond lengths. In the second Si site, Si(2) is bonded in a 5-coordinate geometry to one Ba(1), one Hf(1), and three equivalent Si(1) atoms.