data_CaTa2Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.74
_cell_length_b   4.74
_cell_length_c   4.74
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaTa2Cu
_chemical_formula_sum   'Ca1 Ta2 Cu1'
_cell_volume   75.49
_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  Ca0  1  0.0  0.0  0.0  1.0
  Ta  Ta2  1  0.35  0.35  0.35  1.0
  Ta  Ta3  1  0.68  0.68  0.68  1.0
  Cu  Cu1  1  0.03  0.03  0.03  1.0

data_CaTa2Cu
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.74
_cell_length_b   4.74
_cell_length_c   11.62
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CaTa2Cu
_chemical_formula_sum   'Ca3 Ta6 Cu3'
_cell_volume   226.48
_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  0.32  1.0
  Ta  Ta2  3  0.0  0.0  0.65  1.0
  Cu  Cu3  3  0.0  0.0  0.97  1.0

Ca Ta Ta Cu
Ca Ta Ta Cu 0 3 o o o 0 1 o o - 0 1 o - o 0 1 - o o 0 2 o - - 0 2 - o - 0 2 - - o 1 3 o o + 1 3 o + o 1 3 + o o 1 2 - o o 1 2 o - o 1 2 o o - 2 3 o + + 2 3 + o + 2 3 + + o 
CaTa2Cu crystallizes in the trigonal R3m space group. Ca(1) is bonded in a single-bond geometry to three equivalent Ta(1), four equivalent Ta(2), and one Cu(1) atom. All Ca(1)-Ta(1) bond lengths are 2.75 Å. There are three shorter (2.74 Å) and one longer (3.75 Å) Ca(1)-Ta(2) bond length. The Ca(1)-Cu(1) bond length is 0.37 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 11-coordinate geometry to three equivalent Ca(1), four equivalent Ta(2), and four equivalent Cu(1) atoms. There are three shorter (2.74 Å) and one longer (3.75 Å) Ta(1)-Ta(2) bond length. There are three shorter (2.74 Å) and one longer (3.75 Å) Ta(1)-Cu(1) bond length. In the second Ta site, Ta(2) is bonded in a 11-coordinate geometry to four equivalent Ca(1), four equivalent Ta(1), and three equivalent Cu(1) atoms. All Ta(2)-Cu(1) bond lengths are 2.75 Å. Cu(1) is bonded in a single-bond geometry to one Ca(1), three equivalent Ta(2), and four equivalent Ta(1) atoms.