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  0.48  0.48  0.48  1.0
  Li  Li1  1  0.0  0.0  0.0  1.0
  Mg  Mg2  1  0.83  0.83  0.83  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  0.52  1.0
  Mg  Mg3  3  0.0  0.0  0.17  1.0

Na Li Li Mg
NaLi2Mg crystallizes in the trigonal R3m space group. Na(1) is bonded in a 2-coordinate geometry to one Li(1) and one Mg(1) atom. The Na(1)-Li(1) bond length is 2.21 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) and three equivalent Mg(1) atoms to form LiNaMg3 trigonal pyramids that share  a cornercorner with one Mg(1)NaLi4 trigonal bipyramid and corners with six equivalent Li(1)NaMg3 trigonal pyramids. All Li(1)-Mg(1) bond lengths are 2.99 Å. In the second Li site, Li(2) is bonded in a distorted single-bond geometry to one Mg(1) atom. The Li(2)-Mg(1) bond length is 2.21 Å. Mg(1) is bonded to one Na(1), one Li(2), and three equivalent Li(1) atoms to form distorted MgNaLi4 trigonal bipyramids that share corners with six equivalent Mg(1)NaLi4 trigonal bipyramids and  a cornercorner with one Li(1)NaMg3 trigonal pyramid.