data_LiLaAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.55
_cell_length_b   4.55
_cell_length_c   4.55
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   LiLaAs
_chemical_formula_sum   'Li1 La1 As1'
_cell_volume   66.71
_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  Li2  1  0.0  0.0  0.0  1.0
  La  La1  1  0.83  0.83  0.83  1.0
  As  As0  1  0.61  0.61  0.61  1.0

data_LiLaAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.55
_cell_length_b   4.55
_cell_length_c   11.15
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   LiLaAs
_chemical_formula_sum   'Li3 La3 As3'
_cell_volume   200.13
_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  3  0.0  0.0  0.0  1.0
  La  La1  3  0.0  0.0  0.17  1.0
  As  As2  3  0.0  0.0  0.39  1.0

Li La As
Li La As 0 1 - - - 0 2 o - - 0 2 - o - 0 2 - - o 1 2 o + o 1 2 + o o 1 2 o o + 1 2 o o o 
LiLaAs is half-Heusler structured and crystallizes in the trigonal R3m space group. Li(1) is bonded in a 4-coordinate geometry to one La(1) and three equivalent As(1) atoms. The Li(1)-La(1) bond length is 1.91 Å. All Li(1)-As(1) bond lengths are 2.70 Å. La(1) is bonded in a 2-coordinate geometry to one Li(1) and four equivalent As(1) atoms. There is one shorter (2.44 Å) and three longer (2.92 Å) La(1)-As(1) bond lengths. As(1) is bonded in a 7-coordinate geometry to three equivalent Li(1) and four equivalent La(1) atoms.