data_CaTa2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.79
_cell_length_b   4.79
_cell_length_c   4.79
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaTa2As
_chemical_formula_sum   'Ca1 Ta2 As1'
_cell_volume   77.49
_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
  Ca  Ca1  1  0.0  0.0  0.0  1.0
  Ta  Ta2  1  0.08  0.08  0.08  1.0
  Ta  Ta3  1  0.38  0.38  0.38  1.0
  As  As0  1  0.69  0.69  0.69  1.0

data_CaTa2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.79
_cell_length_b   4.79
_cell_length_c   11.72
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CaTa2As
_chemical_formula_sum   'Ca3 Ta6 As3'
_cell_volume   232.47
_cell_formula_units_Z   3
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
  Ca  Ca0  3  0.0  0.0  0.0  1.0
  Ta  Ta1  3  0.0  0.0  0.62  1.0
  Ta  Ta2  3  0.0  0.0  0.92  1.0
  As  As3  3  0.0  0.0  0.31  1.0

Ca Ta Ta As
CaTa2As crystallizes in the trigonal R3m space group. Ca(1) is bonded in a single-bond geometry to one Ta(1) and four equivalent As(1) atoms. The Ca(1)-Ta(1) bond length is 0.89 Å. There are three shorter (2.78 Å) and one longer (3.61 Å) Ca(1)-As(1) bond length. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a single-bond geometry to one Ca(1) and three equivalent As(1) atoms. All Ta(1)-As(1) bond lengths are 2.83 Å. In the second Ta site, Ta(2) is bonded in a 3-coordinate geometry to four equivalent As(1) atoms. There are three shorter (2.78 Å) and one longer (3.61 Å) Ta(2)-As(1) bond length. As(1) is bonded in a 11-coordinate geometry to four equivalent Ca(1), three equivalent Ta(1), and four equivalent Ta(2) atoms.