data_LuCu2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.51
_cell_length_b   4.51
_cell_length_c   4.51
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   LuCu2As
_chemical_formula_sum   'Lu1 Cu2 As1'
_cell_volume   64.93
_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
  Lu  Lu3  1  0.19  0.19  0.19  1.0
  Cu  Cu1  1  0.6  0.6  0.6  1.0
  Cu  Cu2  1  0.79  0.79  0.79  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_LuCu2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.51
_cell_length_b   4.51
_cell_length_c   11.05
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   LuCu2As
_chemical_formula_sum   'Lu3 Cu6 As3'
_cell_volume   194.79
_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
  Lu  Lu0  3  0.0  0.0  0.81  1.0
  Cu  Cu1  3  0.0  0.0  0.21  1.0
  Cu  Cu2  3  0.0  0.0  0.4  1.0
  As  As3  3  0.0  0.0  0.0  1.0

Lu Cu Cu As
Lu Cu Cu As 0 3 o o o 0 2 - - o 0 2 - o - 0 2 o - - 0 1 - o o 0 1 o - o 0 1 o o - 1 3 o + + 1 3 + o + 1 3 + + o 1 2 o o o 2 3 + + + 
LuCu2As crystallizes in the trigonal R3m space group. Lu(1) is bonded in a distorted single-bond geometry to three equivalent Cu(1), three equivalent Cu(2), and one As(1) atom. All Lu(1)-Cu(1) bond lengths are 2.72 Å. All Lu(1)-Cu(2) bond lengths are 2.72 Å. The Lu(1)-As(1) bond length is 2.10 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 7-coordinate geometry to three equivalent Lu(1), one Cu(2), and three equivalent As(1) atoms. The Cu(1)-Cu(2) bond length is 2.10 Å. All Cu(1)-As(1) bond lengths are 2.72 Å. In the second Cu site, Cu(2) is bonded in a 5-coordinate geometry to three equivalent Lu(1), one Cu(1), and one As(1) atom. The Cu(2)-As(1) bond length is 2.37 Å. As(1) is bonded in a 1-coordinate geometry to one Lu(1), one Cu(2), and three equivalent Cu(1) atoms.