data_Na2LaAs
_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   Na2LaAs
_chemical_formula_sum   'Na2 La1 As1'
_cell_volume   95.1
_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
  Na  Na2  1  0.43  0.43  0.43  1.0
  Na  Na3  1  0.81  0.81  0.81  1.0
  La  La1  1  0.62  0.62  0.62  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_Na2LaAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.12
_cell_length_b   5.12
_cell_length_c   12.55
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na2LaAs
_chemical_formula_sum   'Na6 La3 As3'
_cell_volume   285.3
_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
  Na  Na0  3  0.0  0.0  0.19  1.0
  Na  Na1  3  0.0  0.0  0.57  1.0
  La  La2  3  0.0  0.0  0.38  1.0
  As  As3  3  0.0  0.0  0.0  1.0

Na Na La As
Na Na La As 0 3 o o + 0 3 o + o 0 3 + o o 0 1 - o o 0 1 o - o 0 1 o o - 0 2 o o o 1 2 o o o 1 3 + + + 2 3 + + o 2 3 + o + 2 3 o + + 
Na2LaAs crystallizes in the trigonal R3m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one La(1) and three equivalent As(1) atoms to form distorted NaLaAs3 tetrahedra that share corners with six equivalent Na(1)LaAs3 tetrahedra, corners with three equivalent La(1)Na2As3 trigonal bipyramids, and edges with three equivalent La(1)Na2As3 trigonal bipyramids. The Na(1)-La(1) bond length is 2.37 Å. All Na(1)-As(1) bond lengths are 3.22 Å. In the second Na site, Na(2) is bonded in a distorted linear geometry to one La(1) and one As(1) atom. The Na(2)-La(1) bond length is 2.37 Å. The Na(2)-As(1) bond length is 2.37 Å. La(1) is bonded to one Na(1), one Na(2), and three equivalent As(1) atoms to form distorted LaNa2As3 trigonal bipyramids that share corners with three equivalent Na(1)LaAs3 tetrahedra, corners with six equivalent La(1)Na2As3 trigonal bipyramids, and edges with three equivalent Na(1)LaAs3 tetrahedra. All La(1)-As(1) bond lengths are 3.01 Å. As(1) is bonded in a 1-coordinate geometry to one Na(2), three equivalent Na(1), and three equivalent La(1) atoms.