data_Ta2NiSn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.28
_cell_length_b   9.28
_cell_length_c   9.28
_cell_angle_alpha   18.57
_cell_angle_beta   18.57
_cell_angle_gamma   18.57
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2NiSn
_chemical_formula_sum   'Ta2 Ni1 Sn1'
_cell_volume   70.73
_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
  Ta  Ta2  1  0.0  0.0  0.07  1.0
  Ta  Ta3  1  0.0  0.0  0.27  1.0
  Ni  Ni0  1  0.0  0.0  0.0  1.0
  Sn  Sn1  1  0.0  0.0  0.67  1.0

data_Ta2NiSn
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.19
_cell_length_b   2.99
_cell_length_c   9.28
_cell_angle_alpha   90.0
_cell_angle_beta   100.74
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ta2NiSn
_chemical_formula_sum   'Ta4 Ni2 Sn2'
_cell_volume   141.46
_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
  Ta  Ta0  2  0.0  0.0  0.73  1.0
  Ta  Ta1  2  0.0  0.0  0.93  1.0
  Ni  Ni2  2  0.0  0.0  0.0  1.0
  Sn  Sn3  2  0.0  0.0  0.33  1.0

Ta Ta Ni Sn
Ta Ta Ni Sn 0 2 o o o 0 1 o o o 2 3 o o - 3 3 o + - 3 3 + - o 3 3 + o - 
Ta2NiSn crystallizes in the monoclinic Cm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a single-bond geometry to one Ta(2) and one Ni(1) atom. The Ta(1)-Ta(2) bond length is 1.84 Å. The Ta(1)-Ni(1) bond length is 0.66 Å. In the second Ta site, Ta(2) is bonded in a distorted single-bond geometry to one Ta(1) and one Sn(1) atom. The Ta(2)-Sn(1) bond length is 3.72 Å. Ni(1) is bonded in a single-bond geometry to one Ta(1) and one Sn(1) atom. The Ni(1)-Sn(1) bond length is 3.06 Å. Sn(1) is bonded to one Ta(2), one Ni(1), and six equivalent Sn(1) atoms to form a mixture of edge and corner-sharing SnTaNiSn6 hexagonal bipyramids. All Sn(1)-Sn(1) bond lengths are 2.99 Å.