data_MgNb2Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.89
_cell_length_b   2.89
_cell_length_c   9.25
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNb2Hg
_chemical_formula_sum   'Mg1 Nb2 Hg1'
_cell_volume   77.34
_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  Mg1  1  0.0  0.0  0.91  1.0
  Nb  Nb2  1  0.45  0.45  0.03  1.0
  Nb  Nb3  1  0.0  0.0  0.31  1.0
  Hg  Hg0  1  0.45  0.45  0.64  1.0

data_MgNb2Hg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.09
_cell_length_b   4.09
_cell_length_c   9.25
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgNb2Hg
_chemical_formula_sum   'Mg2 Nb4 Hg2'
_cell_volume   154.68
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.91  1.0
  Nb  Nb1  2  0.0  0.0  0.31  1.0
  Nb  Nb2  2  0.45  0.0  0.03  1.0
  Hg  Hg3  2  0.45  0.0  0.64  1.0

Mg Nb Nb Hg
MgNb2Hg crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 4-coordinate geometry to four equivalent Nb(1) and four equivalent Hg(1) atoms. There are a spread of Mg(1)-Nb(1) bond distances ranging from 2.14-2.53 Å. There are a spread of Mg(1)-Hg(1) bond distances ranging from 3.09-3.37 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Nb(2) atoms. There are a spread of Nb(1)-Nb(2) bond distances ranging from 3.16-3.43 Å. In the second Nb site, Nb(2) is bonded in a 11-coordinate geometry to four equivalent Nb(1), four equivalent Nb(2), and three equivalent Hg(1) atoms. All Nb(2)-Nb(2) bond lengths are 2.89 Å. There is one shorter (3.55 Å) and two longer (3.67 Å) Nb(2)-Hg(1) bond lengths. Hg(1) is bonded in a 9-coordinate geometry to four equivalent Mg(1), three equivalent Nb(2), and four equivalent Hg(1) atoms. All Hg(1)-Hg(1) bond lengths are 2.89 Å.