data_Mg2TlGe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.74
_cell_length_b   3.74
_cell_length_c   6.65
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2TlGe
_chemical_formula_sum   'Mg2 Tl1 Ge1'
_cell_volume   92.96
_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  0.87  0.87  0.45  1.0
  Mg  Mg2  1  0.0  0.0  0.59  1.0
  Tl  Tl3  1  0.87  0.87  0.33  1.0
  Ge  Ge0  1  0.0  0.0  0.26  1.0

data_Mg2TlGe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.29
_cell_length_b   5.29
_cell_length_c   6.65
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg2TlGe
_chemical_formula_sum   'Mg4 Tl2 Ge2'
_cell_volume   185.93
_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  0.59  1.0
  Mg  Mg1  2  0.37  0.5  0.45  1.0
  Tl  Tl2  2  0.37  0.5  0.33  1.0
  Ge  Ge3  2  0.0  0.0  0.26  1.0

Mg Mg Tl Ge
Mg Mg Tl Ge 0 2 o o o 0 1 + + o 2 3 + + o 
Mg2TlGe is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Mg2TlGe clusters. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted single-bond geometry to one Mg(2) and one Tl(1) atom. The Mg(1)-Mg(2) bond length is 1.15 Å. The Mg(1)-Tl(1) bond length is 0.79 Å. In the second Mg site, Mg(2) is bonded in a single-bond geometry to one Mg(1) atom. Tl(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one Ge(1) atom. The Tl(1)-Ge(1) bond length is 0.82 Å. Ge(1) is bonded in a single-bond geometry to one Tl(1) atom.