data_KCuAs4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.82
_cell_length_b   5.82
_cell_length_c   5.82
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KCuAs4
_chemical_formula_sum   'K1 Cu1 As4'
_cell_volume   139.62
_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
  K  K5  1  0.0  0.0  0.0  1.0
  Cu  Cu4  1  0.06  0.06  0.06  1.0
  As  As0  1  0.2  0.2  0.03  1.0
  As  As1  1  0.03  0.03  0.03  1.0
  As  As2  1  0.03  0.2  0.2  1.0
  As  As3  1  0.2  0.03  0.2  1.0

data_KCuAs4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.82
_cell_length_b   5.82
_cell_length_c   14.26
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   KCuAs4
_chemical_formula_sum   'K3 Cu3 As12'
_cell_volume   418.85
_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
  K  K0  3  0.0  0.0  0.0  1.0
  Cu  Cu1  3  0.0  0.0  0.94  1.0
  As  As2  9  0.11  0.06  0.85  1.0
  As  As3  3  0.0  0.0  0.97  1.0

K Cu As As As As
K Cu As As As As 0 3 o o o 1 3 o o o 2 5 o o o 2 4 o o o 4 5 o o o 
KCuAs4 is Copper structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three KCuAs4 clusters. K(1) is bonded in a single-bond geometry to one As(2) atom. The K(1)-As(2) bond length is 0.48 Å. Cu(1) is bonded in a distorted single-bond geometry to one As(2) and three equivalent As(1) atoms. The Cu(1)-As(2) bond length is 0.35 Å. All Cu(1)-As(1) bond lengths are 1.36 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 3-coordinate geometry to one Cu(1) and two equivalent As(1) atoms. Both As(1)-As(1) bond lengths are 0.97 Å. In the second As site, As(2) is bonded in a linear geometry to one K(1) and one Cu(1) atom.