data_Ba2HfTa
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.38
_cell_length_b   12.38
_cell_length_c   12.38
_cell_angle_alpha   15.59
_cell_angle_beta   15.59
_cell_angle_gamma   15.59
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2HfTa
_chemical_formula_sum   'Ba2 Hf1 Ta1'
_cell_volume   119.34
_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  0.66  1.0
  Ba  Ba1  1  0.0  0.0  0.02  1.0
  Hf  Hf2  1  0.0  0.0  0.0  1.0
  Ta  Ta3  1  0.0  0.0  0.34  1.0

data_Ba2HfTa
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.82
_cell_length_b   3.36
_cell_length_c   12.38
_cell_angle_alpha   90.0
_cell_angle_beta   99.01
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ba2HfTa
_chemical_formula_sum   'Ba4 Hf2 Ta2'
_cell_volume   238.68
_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  0.34  1.0
  Ba  Ba1  2  0.0  0.0  0.98  1.0
  Hf  Hf2  2  0.0  0.0  0.0  1.0
  Ta  Ta3  2  0.0  0.0  0.66  1.0

Ba Ba Hf Ta
Ba Ba Hf Ta 0 0 o + - 0 0 + - o 0 0 + o - 0 3 o o o 1 2 o o o 1 3 o o o 3 3 o + - 3 3 + - o 3 3 + o - 
Ba2HfTa crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent Ba(1), one Hf(1), and one Ta(1) atom to form BaBa6HfTa hexagonal bipyramids that share corners with six equivalent Ba(1)Ba6HfTa hexagonal bipyramids, edges with six equivalent Ta(1)Ba2Ta6 hexagonal bipyramids, and edges with twelve equivalent Ba(1)Ba6HfTa hexagonal bipyramids. All Ba(1)-Ba(1) bond lengths are 3.36 Å. The Ba(1)-Hf(1) bond length is 4.25 Å. The Ba(1)-Ta(1) bond length is 3.97 Å. In the second Ba site, Ba(2) is bonded in a single-bond geometry to one Hf(1) and one Ta(1) atom. The Ba(2)-Hf(1) bond length is 0.19 Å. The Ba(2)-Ta(1) bond length is 3.97 Å. Hf(1) is bonded in a single-bond geometry to one Ba(1) and one Ba(2) atom. Ta(1) is bonded to one Ba(1), one Ba(2), and six equivalent Ta(1) atoms to form TaBa2Ta6 hexagonal bipyramids that share corners with six equivalent Ta(1)Ba2Ta6 hexagonal bipyramids, edges with six equivalent Ba(1)Ba6HfTa hexagonal bipyramids, and edges with twelve equivalent Ta(1)Ba2Ta6 hexagonal bipyramids. All Ta(1)-Ta(1) bond lengths are 3.36 Å.