data_LaAs2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.11
_cell_length_b   5.11
_cell_length_c   5.11
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   LaAs2Se
_chemical_formula_sum   'La1 As2 Se1'
_cell_volume   94.46
_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
  La  La2  1  0.42  0.42  0.42  1.0
  As  As0  1  0.81  0.81  0.81  1.0
  As  As1  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.61  0.61  0.61  1.0

data_LaAs2Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.11
_cell_length_b   5.11
_cell_length_c   12.52
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   LaAs2Se
_chemical_formula_sum   'La3 As6 Se3'
_cell_volume   283.37
_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
  La  La0  3  0.0  0.0  0.58  1.0
  As  As1  3  0.0  0.0  0.0  1.0
  As  As2  3  0.0  0.0  0.19  1.0
  Se  Se3  3  0.0  0.0  0.39  1.0

La As As Se
LaAs2Se crystallizes in the trigonal R3m space group. La(1) is bonded in a distorted single-bond geometry to three equivalent As(1), three equivalent As(2), and one Se(1) atom. All La(1)-As(1) bond lengths are 3.02 Å. All La(1)-As(2) bond lengths are 3.15 Å. The La(1)-Se(1) bond length is 2.41 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to three equivalent La(1), one As(2), and one Se(1) atom. The As(1)-As(2) bond length is 2.41 Å. The As(1)-Se(1) bond length is 2.41 Å. In the second As site, As(2) is bonded to three equivalent La(1), one As(1), and three equivalent Se(1) atoms to form distorted edge-sharing AsLa3AsSe3 hexagonal pyramids. All As(2)-Se(1) bond lengths are 3.02 Å. Se(1) is bonded in a distorted linear geometry to one La(1), one As(1), and three equivalent As(2) atoms.