data_Na2MgB
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.69
_cell_length_b   4.69
_cell_length_c   4.69
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2MgB
_chemical_formula_sum   'Na2 Mg1 B1'
_cell_volume   72.74
_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  0.31  0.31  0.31  1.0
  Na  Na3  1  0.97  0.97  0.97  1.0
  Mg  Mg1  1  0.66  0.66  0.66  1.0
  B  B0  1  0.0  0.0  0.0  1.0

data_Na2MgB
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.69
_cell_length_b   4.69
_cell_length_c   11.48
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na2MgB
_chemical_formula_sum   'Na6 Mg3 B3'
_cell_volume   218.22
_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  0.03  1.0
  Na  Na1  3  0.0  0.0  0.69  1.0
  Mg  Mg2  3  0.0  0.0  0.34  1.0
  B  B3  3  0.0  0.0  0.0  1.0

Na Na Mg B
Na Na Mg B 0 3 o o + 0 3 o + o 0 3 + o o 0 1 - - o 0 1 - o - 0 1 o - - 0 2 - o o 0 2 o - o 0 2 o o - 1 3 + + + 1 2 + o o 1 2 o + o 1 2 o o + 2 3 o + + 2 3 + o + 2 3 + + o 
Na2MgB crystallizes in the trigonal R3m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar geometry to three equivalent Mg(1) and three equivalent B(1) atoms. All Na(1)-Mg(1) bond lengths are 2.71 Å. All Na(1)-B(1) bond lengths are 2.72 Å. In the second Na site, Na(2) is bonded in a single-bond geometry to four equivalent Mg(1) and one B(1) atom. There are three shorter (2.72 Å) and one longer (3.59 Å) Na(2)-Mg(1) bond length. The Na(2)-B(1) bond length is 0.35 Å. Mg(1) is bonded in a 10-coordinate geometry to three equivalent Na(1), four equivalent Na(2), and three equivalent B(1) atoms. All Mg(1)-B(1) bond lengths are 2.71 Å. B(1) is bonded in a single-bond geometry to one Na(2), three equivalent Na(1), and three equivalent Mg(1) atoms.