data_BaCu4As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.32
_cell_length_b   5.32
_cell_length_c   5.32
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaCu4As
_chemical_formula_sum   'Ba1 Cu4 As1'
_cell_volume   106.56
_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
  Ba  Ba1  1  0.88  0.88  0.88  1.0
  Cu  Cu2  1  0.82  0.82  0.71  1.0
  Cu  Cu3  1  0.82  0.71  0.82  1.0
  Cu  Cu4  1  0.71  0.82  0.82  1.0
  Cu  Cu5  1  0.71  0.71  0.71  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_BaCu4As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.32
_cell_length_b   5.32
_cell_length_c   13.03
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BaCu4As
_chemical_formula_sum   'Ba3 Cu12 As3'
_cell_volume   319.67
_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
  Ba  Ba0  3  0.0  0.0  0.12  1.0
  Cu  Cu1  9  0.07  0.04  0.22  1.0
  Cu  Cu2  3  0.0  0.0  0.29  1.0
  As  As3  3  0.0  0.0  0.0  1.0

Ba Cu Cu Cu Cu As
BaCu4As crystallizes in the trigonal R3m space group. Ba(1) is bonded in a distorted single-bond geometry to three equivalent Cu(1) and one As(1) atom. All Ba(1)-Cu(1) bond lengths are 1.35 Å. The Ba(1)-As(1) bond length is 1.55 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 5-coordinate geometry to one Ba(1), one Cu(2), two equivalent Cu(1), and one As(1) atom. The Cu(1)-Cu(2) bond length is 1.03 Å. Both Cu(1)-Cu(1) bond lengths are 0.59 Å. The Cu(1)-As(1) bond length is 3.11 Å. In the second Cu site, Cu(2) is bonded in a 3-coordinate geometry to three equivalent Cu(1) atoms. As(1) is bonded in a single-bond geometry to one Ba(1) and three equivalent Cu(1) atoms.