data_Li4CuSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.12
_cell_length_b   5.12
_cell_length_c   5.12
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Li4CuSe
_chemical_formula_sum   'Li4 Cu1 Se1'
_cell_volume   94.87
_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
  Li  Li1  1  0.53  0.53  0.71  1.0
  Li  Li2  1  0.53  0.71  0.53  1.0
  Li  Li3  1  0.71  0.53  0.53  1.0
  Li  Li4  1  0.71  0.71  0.71  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Se  Se5  1  0.43  0.43  0.43  1.0

data_Li4CuSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.12
_cell_length_b   5.12
_cell_length_c   12.54
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Li4CuSe
_chemical_formula_sum   'Li12 Cu3 Se3'
_cell_volume   284.61
_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
  Li  Li0  9  0.06  0.12  0.41  1.0
  Li  Li1  3  0.0  0.0  0.29  1.0
  Cu  Cu2  3  0.0  0.0  0.0  1.0
  Se  Se3  3  0.0  0.0  0.57  1.0

Li Li Li Li Cu Se
Li Li Li Li Cu Se 0 2 o o o 0 1 o o o 0 3 o o o 0 4 + o + 0 4 o + + 0 5 o o o 1 2 o o o 1 3 o o o 1 4 + + o 1 4 o + + 1 5 o o o 2 3 o o o 2 4 + + o 2 4 + o + 2 5 o o o 3 4 + + o 3 4 + o + 3 4 o + + 4 5 - o o 4 5 o - o 4 5 o o - 
Li4CuSe crystallizes in the trigonal R3m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 3-coordinate geometry to one Li(2), two equivalent Li(1), two equivalent Cu(1), and one Se(1) atom. The Li(1)-Li(2) bond length is 1.66 Å. Both Li(1)-Li(1) bond lengths are 0.96 Å. Both Li(1)-Cu(1) bond lengths are 2.89 Å. The Li(1)-Se(1) bond length is 2.07 Å. In the second Li site, Li(2) is bonded in a 9-coordinate geometry to three equivalent Li(1), three equivalent Cu(1), and three equivalent Se(1) atoms. All Li(2)-Cu(1) bond lengths are 3.01 Å. All Li(2)-Se(1) bond lengths are 3.02 Å. Cu(1) is bonded in a 12-coordinate geometry to three equivalent Li(2), six equivalent Li(1), and three equivalent Se(1) atoms. All Cu(1)-Se(1) bond lengths are 3.19 Å. Se(1) is bonded in a 6-coordinate geometry to three equivalent Li(1), three equivalent Li(2), and three equivalent Cu(1) atoms.