data_TaAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.37
_cell_length_b   5.37
_cell_length_c   5.37
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TaAs2
_chemical_formula_sum   'Ta2 As4'
_cell_volume   109.33
_cell_formula_units_Z   2
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  Ta4  1  0.0  0.0  0.0  1.0
  Ta  Ta5  1  0.9  0.9  0.9  1.0
  As  As0  1  0.85  0.85  0.74  1.0
  As  As1  1  0.85  0.74  0.85  1.0
  As  As2  1  0.74  0.74  0.74  1.0
  As  As3  1  0.74  0.85  0.85  1.0

data_TaAs2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.37
_cell_length_b   5.37
_cell_length_c   13.15
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   TaAs2
_chemical_formula_sum   'Ta6 As12'
_cell_volume   328.0
_cell_formula_units_Z   6
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.0  1.0
  Ta  Ta1  3  0.0  0.0  0.1  1.0
  As  As2  9  0.07  0.03  0.19  1.0
  As  As3  3  0.0  0.0  0.26  1.0

Ta Ta As As As As
Ta Ta As As As As 0 1 - - - 1 5 o o o 1 3 o o o 1 2 o o o 2 3 o o o 2 5 o o o 2 4 o o o 3 5 o o o 3 4 o o o 4 5 o o o 
TaAs2 crystallizes in the trigonal R3m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one Ta(2), three equivalent As(1), and three equivalent As(2) atoms. The Ta(1)-Ta(2) bond length is 1.35 Å. All Ta(1)-As(1) bond lengths are 3.38 Å. All Ta(1)-As(2) bond lengths are 3.26 Å. In the second Ta site, Ta(2) is bonded in a distorted rectangular see-saw-like geometry to one Ta(1) and three equivalent As(1) atoms. All Ta(2)-As(1) bond lengths are 1.17 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 2-coordinate geometry to one Ta(1), one Ta(2), one As(2), and two equivalent As(1) atoms. The As(1)-As(2) bond length is 0.95 Å. Both As(1)-As(1) bond lengths are 0.55 Å. In the second As site, As(2) is bonded in a 6-coordinate geometry to three equivalent Ta(1) and three equivalent As(1) atoms.