data_TaCuSn2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.18
_cell_length_b   9.18
_cell_length_c   9.18
_cell_angle_alpha   19.88
_cell_angle_beta   19.88
_cell_angle_gamma   19.88
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TaCuSn2
_chemical_formula_sum   'Ta1 Cu1 Sn2'
_cell_volume   78.4
_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  Ta3  1  0.0  0.0  0.5  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Sn  Sn1  1  0.0  0.0  0.9  1.0
  Sn  Sn2  1  0.0  0.0  0.1  1.0

data_TaCuSn2
_symmetry_space_group_name_H-M   C2/m
_cell_length_a   5.49
_cell_length_b   3.17
_cell_length_c   9.18
_cell_angle_alpha   90.0
_cell_angle_beta   101.5
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   12
_chemical_formula_structural   TaCuSn2
_chemical_formula_sum   'Ta2 Cu2 Sn4'
_cell_volume   156.81
_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, y, -z'
  4  'x, -y, z'
  5  'x+1/2, y+1/2, z'
  6  '-x+1/2, -y+1/2, -z'
  7  '-x+1/2, y+1/2, -z'
  8  '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  0.0  1.0
  Cu  Cu1  2  0.0  0.0  0.5  1.0
  Sn  Sn2  4  -0.0  0.0  0.4  1.0

Ta Cu Sn Sn
Ta Cu Sn Sn 0 0 o + - 0 0 + - o 0 0 + o - 0 3 o o o 0 2 o o o 1 2 o o - 1 3 o o o 
TaCuSn2 crystallizes in the monoclinic C2/m space group. Ta(1) is bonded to six equivalent Ta(1) and two equivalent Sn(1) atoms to form a mixture of edge and corner-sharing TaTa6Sn2 hexagonal bipyramids. All Ta(1)-Ta(1) bond lengths are 3.17 Å. Both Ta(1)-Sn(1) bond lengths are 3.64 Å. Cu(1) is bonded in a linear geometry to two equivalent Sn(1) atoms. Both Cu(1)-Sn(1) bond lengths are 0.95 Å. Sn(1) is bonded in a single-bond geometry to one Ta(1) and one Cu(1) atom.