data_Na2SrTa
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.32
_cell_length_b   7.32
_cell_length_c   7.32
_cell_angle_alpha   155.52
_cell_angle_beta   132.8
_cell_angle_gamma   53.87
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2SrTa
_chemical_formula_sum   'Na2 Sr1 Ta1'
_cell_volume   118.55
_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  0.55  0.0  0.61  1.0
  Na  Na1  1  0.0  0.93  0.91  1.0
  Sr  Sr2  1  0.0  0.0  0.0  1.0
  Ta  Ta3  1  0.0  0.0  0.52  1.0

data_Na2SrTa
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.1
_cell_length_b   5.86
_cell_length_c   7.32
_cell_angle_alpha   113.6
_cell_angle_beta   102.24
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2SrTa
_chemical_formula_sum   'Na2 Sr1 Ta1'
_cell_volume   118.55
_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  0.61  0.06  1.0
  Na  Na1  1  0.07  0.98  0.98  1.0
  Sr  Sr2  1  0.0  0.0  0.0  1.0
  Ta  Ta3  1  0.0  0.52  0.52  1.0

Na Na Sr Ta
Na Na Sr Ta 0 1 + - o 0 2 + o + 0 3 + o o 0 3 o o o 1 2 o + + 1 3 o + o 2 3 o o o 2 3 o o - 3 3 o + + 
Na2SrTa crystallizes in the triclinic P1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Sr(1), and two equivalent Ta(1) atoms. The Na(1)-Na(2) bond length is 2.48 Å. Both Na(1)-Na(1) bond lengths are 3.10 Å. There is one shorter (2.49 Å) and one longer (3.42 Å) Na(1)-Sr(1) bond length. There is one shorter (3.63 Å) and one longer (3.75 Å) Na(1)-Ta(1) bond length. In the second Na site, Na(2) is bonded in a single-bond geometry to one Na(1), one Sr(1), and one Ta(1) atom. The Na(2)-Sr(1) bond length is 0.27 Å. The Na(2)-Ta(1) bond length is 3.33 Å. Sr(1) is bonded in a single-bond geometry to one Na(2), two equivalent Na(1), and one Ta(1) atom. The Sr(1)-Ta(1) bond length is 3.83 Å. Ta(1) is bonded to one Na(2), two equivalent Na(1), one Sr(1), and two equivalent Ta(1) atoms to form distorted corner-sharing TaNa3SrTa2 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. Both Ta(1)-Ta(1) bond lengths are 3.10 Å.