data_CaTaCu4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   5.07
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaTaCu4
_chemical_formula_sum   'Ca1 Ta1 Cu4'
_cell_volume   92.02
_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  Ta5  1  0.37  0.37  0.37  1.0
  Cu  Cu1  1  0.48  0.48  0.69  1.0
  Cu  Cu2  1  0.48  0.69  0.48  1.0
  Cu  Cu3  1  0.69  0.48  0.48  1.0
  Cu  Cu4  1  0.69  0.69  0.69  1.0

data_CaTaCu4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   12.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CaTaCu4
_chemical_formula_sum   'Ca3 Ta3 Cu12'
_cell_volume   276.05
_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  0.63  1.0
  Cu  Cu2  9  0.07  0.14  0.45  1.0
  Cu  Cu3  3  0.0  0.0  0.31  1.0

Ca Ta Cu Cu Cu Cu
CaTaCu4 crystallizes in the trigonal R3m space group. Ca(1) is bonded in a 15-coordinate geometry to three equivalent Ta(1), three equivalent Cu(2), and nine equivalent Cu(1) atoms. All Ca(1)-Ta(1) bond lengths are 2.97 Å. All Ca(1)-Cu(2) bond lengths are 2.94 Å. There are six shorter (3.05 Å) and three longer (3.52 Å) Ca(1)-Cu(1) bond lengths. Ta(1) is bonded to three equivalent Ca(1), three equivalent Cu(2), and six equivalent Cu(1) atoms to form a mixture of distorted edge and corner-sharing TaCa3Cu9 cuboctahedra. All Ta(1)-Cu(2) bond lengths are 2.93 Å. There are three shorter (2.23 Å) and three longer (3.04 Å) Ta(1)-Cu(1) bond lengths. There are two inequivalent Cu sites. In the first Cu site, Cu(2) is bonded in a 9-coordinate geometry to three equivalent Ca(1), three equivalent Ta(1), and three equivalent Cu(1) atoms. All Cu(2)-Cu(1) bond lengths are 1.88 Å. In the second Cu site, Cu(1) is bonded in a 2-coordinate geometry to three equivalent Ca(1), two equivalent Ta(1), one Cu(2), and two equivalent Cu(1) atoms. Both Cu(1)-Cu(1) bond lengths are 1.09 Å.