data_Ta4Os
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.43
_cell_length_b   5.43
_cell_length_c   5.43
_cell_angle_alpha   95.05
_cell_angle_beta   95.05
_cell_angle_gamma   145.48
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta4Os
_chemical_formula_sum   'Ta4 Os1'
_cell_volume   86.61
_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  Ta1  1  0.16  0.29  0.61  1.0
  Ta  Ta2  1  0.96  0.51  0.0  1.0
  Ta  Ta3  1  0.51  0.38  0.0  1.0
  Ta  Ta4  1  0.71  0.16  0.61  1.0
  Os  Os0  1  0.0  0.0  0.0  1.0

data_Ta4Os
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.22
_cell_length_b   5.43
_cell_length_c   5.43
_cell_angle_alpha   84.95
_cell_angle_beta   72.74
_cell_angle_gamma   72.74
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta4Os
_chemical_formula_sum   'Ta4 Os1'
_cell_volume   86.61
_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  Ta0  1  0.16  0.55  0.39  1.0
  Ta  Ta1  1  0.29  0.87  0.39  1.0
  Ta  Ta2  1  0.38  0.13  0.0  1.0
  Ta  Ta3  1  0.51  0.45  0.0  1.0
  Os  Os4  1  0.0  0.0  0.0  1.0

Ta Ta Ta Ta Os
Ta Ta Ta Ta Os 0 3 - o o 1 2 o o o 1 3 o o - 2 4 o o o 2 4 + + o 
Ta4Os crystallizes in the triclinic P1 space group. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 6-coordinate geometry to one Ta(3), two equivalent Ta(4), and three equivalent Os(1) atoms. The Ta(1)-Ta(3) bond length is 2.43 Å. There is one shorter (1.91 Å) and one longer (2.82 Å) Ta(1)-Ta(4) bond length. There are a spread of Ta(1)-Os(1) bond distances ranging from 2.52-3.25 Å. In the second Ta site, Ta(2) is bonded in a distorted rectangular see-saw-like geometry to one Ta(3), one Ta(4), and two equivalent Os(1) atoms. The Ta(2)-Ta(3) bond length is 1.91 Å. The Ta(2)-Ta(4) bond length is 2.11 Å. There is one shorter (2.50 Å) and one longer (2.94 Å) Ta(2)-Os(1) bond length. In the third Ta site, Ta(3) is bonded in a 2-coordinate geometry to one Ta(1), one Ta(2), and two equivalent Os(1) atoms. There is one shorter (1.57 Å) and one longer (1.93 Å) Ta(3)-Os(1) bond length. In the fourth Ta site, Ta(4) is bonded in a distorted water-like geometry to one Ta(2) and two equivalent Ta(1) atoms. Os(1) is bonded in a 2-coordinate geometry to two equivalent Ta(2), two equivalent Ta(3), and three equivalent Ta(1) atoms.