data_Ta2MnSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.58
_cell_length_b   4.58
_cell_length_c   3.14
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   102.07
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2MnSe
_chemical_formula_sum   'Ta2 Mn1 Se1'
_cell_volume   64.29
_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  0.44  0.22  0.57  1.0
  Ta  Ta3  1  0.44  0.78  0.57  1.0
  Mn  Mn0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.88  0.0  0.0  1.0

data_Ta2MnSe
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.14
_cell_length_b   4.58
_cell_length_c   4.58
_cell_angle_alpha   102.07
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2MnSe
_chemical_formula_sum   'Ta2 Mn1 Se1'
_cell_volume   64.29
_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  0.57  0.44  0.22  1.0
  Ta  Ta1  1  0.57  0.44  0.78  1.0
  Mn  Mn2  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.0  0.88  0.0  1.0

Ta Ta Mn Se
Ta Ta Mn Se 0 2 o o + 0 1 o - o 1 3 o + + 2 3 - o o 
Ta2MnSe crystallizes in the triclinic P1 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 6-coordinate geometry to two equivalent Ta(2), two equivalent Mn(1), and two equivalent Se(1) atoms. There is one shorter (2.01 Å) and one longer (2.56 Å) Ta(1)-Ta(2) bond length. There is one shorter (2.46 Å) and one longer (2.72 Å) Ta(1)-Mn(1) bond length. There is one shorter (2.78 Å) and one longer (3.01 Å) Ta(1)-Se(1) bond length. In the second Ta site, Ta(2) is bonded in a 3-coordinate geometry to two equivalent Ta(1) and two equivalent Se(1) atoms. There is one shorter (2.46 Å) and one longer (2.72 Å) Ta(2)-Se(1) bond length. Mn(1) is bonded in a single-bond geometry to two equivalent Ta(1) and one Se(1) atom. The Mn(1)-Se(1) bond length is 0.55 Å. Se(1) is bonded in a single-bond geometry to two equivalent Ta(1), two equivalent Ta(2), and one Mn(1) atom.