data_LiMgN
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.54
_cell_length_b   3.54
_cell_length_c   3.54
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   LiMgN
_chemical_formula_sum   'Li1 Mg1 N1'
_cell_volume   31.47
_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  Li0  1  0.0  0.0  0.0  1.0
  Mg  Mg1  1  0.51  0.51  0.51  1.0
  N  N2  1  0.76  0.76  0.76  1.0

data_LiMgN
_symmetry_space_group_name_H-M   R3m
_cell_length_a   3.54
_cell_length_b   3.54
_cell_length_c   8.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   LiMgN
_chemical_formula_sum   'Li3 Mg3 N3'
_cell_volume   94.41
_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
  Mg  Mg1  3  0.0  0.0  0.49  1.0
  N  N2  3  0.0  0.0  0.24  1.0

Li Mg N
Li Mg N 0 2 - - - 0 2 - - o 0 2 o - - 0 2 - o - 0 1 - - o 0 1 - o - 0 1 - o o 0 1 o - - 0 1 o - o 0 1 o o - 1 2 - o o 1 2 o - o 1 2 o o - 1 2 o o o 
LiMgN is half-Heusler structured and crystallizes in the trigonal R3m space group. Li(1) is bonded to four equivalent N(1) atoms to form distorted LiN4 tetrahedra that share corners with four equivalent Mg(1)N4 tetrahedra, corners with twelve equivalent Li(1)N4 tetrahedra, and edges with six equivalent Mg(1)N4 tetrahedra. There is one shorter (2.09 Å) and three longer (2.20 Å) Li(1)-N(1) bond lengths. Mg(1) is bonded to four equivalent N(1) atoms to form distorted MgN4 tetrahedra that share corners with four equivalent Li(1)N4 tetrahedra, corners with twelve equivalent Mg(1)N4 tetrahedra, and edges with six equivalent Li(1)N4 tetrahedra. There are three shorter (2.16 Å) and one longer (2.20 Å) Mg(1)-N(1) bond length. N(1) is bonded in a body-centered cubic geometry to four equivalent Li(1) and four equivalent Mg(1) atoms.