data_Mg2HgB
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.02
_cell_length_b   3.02
_cell_length_c   7.51
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2HgB
_chemical_formula_sum   'Mg2 Hg1 B1'
_cell_volume   68.47
_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
  Mg  Mg2  1  0.51  0.51  0.09  1.0
  Mg  Mg3  1  0.51  0.51  0.41  1.0
  Hg  Hg1  1  0.0  0.0  0.75  1.0
  B  B0  1  0.0  0.0  0.0  1.0

data_Mg2HgB
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   3.02
_cell_length_b   3.02
_cell_length_c   7.51
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   Mg2HgB
_chemical_formula_sum   'Mg2 Hg1 B1'
_cell_volume   68.47
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x, z'
  3  '-x, -y, z'
  4  'y, -x, z'
  5  '-x, y, z'
  6  'y, x, z'
  7  'x, -y, z'
  8  '-y, -x, 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
  Mg  Mg0  1  0.5  0.5  0.09  1.0
  Mg  Mg1  1  0.5  0.5  0.41  1.0
  Hg  Hg2  1  0.0  0.0  0.75  1.0
  B  B3  1  0.0  0.0  0.0  1.0

Mg Mg Hg B
Mg2HgB crystallizes in the monoclinic Cm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Mg(2) and four equivalent B(1) atoms. The Mg(1)-Mg(2) bond length is 2.38 Å. There are a spread of Mg(1)-B(1) bond distances ranging from 2.21-2.29 Å. In the second Mg site, Mg(2) is bonded in a 9-coordinate geometry to one Mg(1), four equivalent Mg(2), and four equivalent Hg(1) atoms. All Mg(2)-Mg(2) bond lengths are 3.02 Å. There are a spread of Mg(2)-Hg(1) bond distances ranging from 3.31-3.37 Å. Hg(1) is bonded in a distorted single-bond geometry to four equivalent Mg(2) and one B(1) atom. The Hg(1)-B(1) bond length is 1.85 Å. B(1) is bonded to four equivalent Mg(1) and one Hg(1) atom to form a mixture of distorted edge and corner-sharing BMg4Hg trigonal bipyramids.