data_NaTaTl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.77
_cell_length_b   4.77
_cell_length_c   4.77
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaTaTl
_chemical_formula_sum   'Na1 Ta1 Tl1'
_cell_volume   76.77
_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
  Na  Na0  1  0.0  0.0  0.0  1.0
  Ta  Ta1  1  0.37  0.37  0.37  1.0
  Tl  Tl2  1  0.69  0.69  0.69  1.0

data_NaTaTl
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.77
_cell_length_b   4.77
_cell_length_c   11.69
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaTaTl
_chemical_formula_sum   'Na3 Ta3 Tl3'
_cell_volume   230.31
_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
  Na  Na0  3  0.0  0.0  0.0  1.0
  Ta  Ta1  3  0.0  0.0  0.63  1.0
  Tl  Tl2  3  0.0  0.0  0.31  1.0

Na Ta Tl
NaTaTl is half-Heusler structured and crystallizes in the trigonal R3m space group. Na(1) is bonded to three equivalent Ta(1) and four equivalent Tl(1) atoms to form distorted NaTa3Tl4 hexagonal pyramids that share corners with six equivalent Tl(1)Na4Ta4 hexagonal bipyramids, corners with four equivalent Ta(1)Na3Tl4 hexagonal pyramids, corners with six equivalent Na(1)Ta3Tl4 hexagonal pyramids, edges with three equivalent Tl(1)Na4Ta4 hexagonal bipyramids, edges with six equivalent Na(1)Ta3Tl4 hexagonal pyramids, and edges with six equivalent Ta(1)Na3Tl4 hexagonal pyramids. All Na(1)-Ta(1) bond lengths are 2.79 Å. There are three shorter (2.76 Å) and one longer (3.66 Å) Na(1)-Tl(1) bond length. Ta(1) is bonded to three equivalent Na(1) and four equivalent Tl(1) atoms to form distorted TaNa3Tl4 hexagonal pyramids that share corners with six equivalent Tl(1)Na4Ta4 hexagonal bipyramids, corners with four equivalent Na(1)Ta3Tl4 hexagonal pyramids, corners with six equivalent Ta(1)Na3Tl4 hexagonal pyramids, edges with three equivalent Tl(1)Na4Ta4 hexagonal bipyramids, edges with six equivalent Na(1)Ta3Tl4 hexagonal pyramids, and edges with six equivalent Ta(1)Na3Tl4 hexagonal pyramids. There are three shorter (2.76 Å) and one longer (3.66 Å) Ta(1)-Tl(1) bond length. Tl(1) is bonded to four equivalent Na(1) and four equivalent Ta(1) atoms to form distorted TlNa4Ta4 hexagonal bipyramids that share corners with six equivalent Na(1)Ta3Tl4 hexagonal pyramids, corners with six equivalent Ta(1)Na3Tl4 hexagonal pyramids, edges with twelve equivalent Tl(1)Na4Ta4 hexagonal bipyramids, edges with three equivalent Na(1)Ta3Tl4 hexagonal pyramids, and edges with three equivalent Ta(1)Na3Tl4 hexagonal pyramids.