data_Ho2TiNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   5.07
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ho2TiNb
_chemical_formula_sum   'Ho2 Ti1 Nb1'
_cell_volume   92.08
_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
  Ho  Ho0  1  0.79  0.79  0.79  1.0
  Ho  Ho1  1  0.38  0.38  0.38  1.0
  Ti  Ti3  1  0.0  0.0  0.0  1.0
  Nb  Nb2  1  0.58  0.58  0.58  1.0

data_Ho2TiNb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   12.42
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ho2TiNb
_chemical_formula_sum   'Ho6 Ti3 Nb3'
_cell_volume   276.23
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Ho  Ho0  3  0.0  0.0  0.21  1.0
  Ho  Ho1  3  0.0  0.0  0.62  1.0
  Ti  Ti2  3  0.0  0.0  0.0  1.0
  Nb  Nb3  3  0.0  0.0  0.42  1.0

Ho Ho Ti Nb
Ho Ho Ti Nb 0 2 + o + 0 2 o + + 0 2 + + o 0 2 + + + 0 3 o o o 0 3 o o + 0 3 + o o 0 3 o + o 0 1 o o + 0 1 o + o 0 1 + o o 1 3 o - o 1 3 - o o 1 3 o o - 1 3 o o o 1 2 o o + 1 2 o + o 1 2 + o o 2 3 - - o 2 3 - o - 2 3 o - - 
Ho2TiNb is Heusler structured and crystallizes in the trigonal R3m space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a distorted linear geometry to four equivalent Ti(1) and one Nb(1) atom. There is one shorter (2.58 Å) and three longer (3.31 Å) Ho(1)-Ti(1) bond lengths. The Ho(1)-Nb(1) bond length is 2.58 Å. In the second Ho site, Ho(2) is bonded in a 4-coordinate geometry to three equivalent Ti(1) and one Nb(1) atom. All Ho(2)-Ti(1) bond lengths are 2.97 Å. The Ho(2)-Nb(1) bond length is 2.58 Å. Ti(1) is bonded in a 10-coordinate geometry to three equivalent Ho(2), four equivalent Ho(1), and three equivalent Nb(1) atoms. All Ti(1)-Nb(1) bond lengths are 3.10 Å. Nb(1) is bonded in a distorted linear geometry to one Ho(1), one Ho(2), and three equivalent Ti(1) atoms.