data_BaMg4Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.23
_cell_length_b   6.23
_cell_length_c   6.23
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaMg4Se
_chemical_formula_sum   'Ba1 Mg4 Se1'
_cell_volume   170.71
_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
  Ba  Ba0  1  0.2  0.2  0.2  1.0
  Mg  Mg1  1  0.29  0.29  0.51  1.0
  Mg  Mg2  1  0.29  0.51  0.29  1.0
  Mg  Mg3  1  0.51  0.29  0.29  1.0
  Mg  Mg4  1  0.51  0.51  0.51  1.0
  Se  Se5  1  0.0  0.0  0.0  1.0

data_BaMg4Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.23
_cell_length_b   6.23
_cell_length_c   15.25
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BaMg4Se
_chemical_formula_sum   'Ba3 Mg12 Se3'
_cell_volume   512.12
_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
  Ba  Ba0  3  0.0  0.0  0.8  1.0
  Mg  Mg1  9  0.07  0.15  0.63  1.0
  Mg  Mg2  3  0.0  0.0  0.49  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Ba Mg Mg Mg Mg Se
BaMg4Se crystallizes in the trigonal R3m space group. Ba(1) is bonded in a 1-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), and one Se(1) atom. All Ba(1)-Mg(1) bond lengths are 2.63 Å. All Ba(1)-Mg(2) bond lengths are 3.61 Å. The Ba(1)-Se(1) bond length is 3.07 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Ba(1), one Mg(2), two equivalent Mg(1), and one Se(1) atom. The Mg(1)-Mg(2) bond length is 2.41 Å. Both Mg(1)-Mg(1) bond lengths are 1.39 Å. The Mg(1)-Se(1) bond length is 2.83 Å. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to three equivalent Ba(1) and three equivalent Mg(1) atoms. Se(1) is bonded in a distorted trigonal pyramidal geometry to one Ba(1) and three equivalent Mg(1) atoms.