data_NaLi2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.16
_cell_length_b   5.16
_cell_length_c   5.16
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaLi2Mg
_chemical_formula_sum   'Na1 Li2 Mg1'
_cell_volume   97.3
_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  Na3  1  0.65  0.65  0.65  1.0
  Li  Li0  1  0.83  0.83  0.83  1.0
  Li  Li1  1  0.0  0.0  0.0  1.0
  Mg  Mg2  1  0.48  0.48  0.48  1.0

data_NaLi2Mg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.16
_cell_length_b   5.16
_cell_length_c   12.65
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaLi2Mg
_chemical_formula_sum   'Na3 Li6 Mg3'
_cell_volume   291.9
_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  0.35  1.0
  Li  Li1  3  0.0  0.0  0.0  1.0
  Li  Li2  3  0.0  0.0  0.17  1.0
  Mg  Mg3  3  0.0  0.0  0.52  1.0

Na Li Li Mg
Na Li Li Mg 0 3 o o o 0 1 o o o 1 2 + + + 
NaLi2Mg crystallizes in the trigonal R3m space group. Na(1) is bonded in a distorted linear geometry to one Li(1), three equivalent Li(2), and one Mg(1) atom. The Na(1)-Li(1) bond length is 2.21 Å. All Na(1)-Li(2) bond lengths are 2.99 Å. The Na(1)-Mg(1) bond length is 2.21 Å. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one Na(1), one Li(2), and three equivalent Mg(1) atoms to form LiNaLiMg3 trigonal bipyramids that share corners with six equivalent Li(1)NaLiMg3 trigonal bipyramids,  a cornercorner with one Mg(1)NaLi3 trigonal pyramid, and corners with three equivalent Li(2)Na3Li trigonal pyramids. The Li(1)-Li(2) bond length is 2.21 Å. All Li(1)-Mg(1) bond lengths are 2.99 Å. In the second Li site, Li(2) is bonded to three equivalent Na(1) and one Li(1) atom to form distorted LiNa3Li trigonal pyramids that share corners with three equivalent Li(1)NaLiMg3 trigonal bipyramids, corners with six equivalent Li(2)Na3Li trigonal pyramids, and edges with three equivalent Mg(1)NaLi3 trigonal pyramids. Mg(1) is bonded to one Na(1) and three equivalent Li(1) atoms to form distorted MgNaLi3 trigonal pyramids that share  a cornercorner with one Li(1)NaLiMg3 trigonal bipyramid, corners with six equivalent Mg(1)NaLi3 trigonal pyramids, and edges with three equivalent Li(2)Na3Li trigonal pyramids.