data_Mg3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.18
_cell_length_b   4.88
_cell_length_c   5.14
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg3Si
_chemical_formula_sum   'Mg3 Si1'
_cell_volume   79.82
_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  Mg0  1  0.59  0.0  0.02  1.0
  Mg  Mg1  1  0.0  0.0  0.51  1.0
  Mg  Mg2  1  0.0  0.44  0.32  1.0
  Si  Si3  1  0.59  0.44  0.72  1.0

data_Mg3Si
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.18
_cell_length_b   4.88
_cell_length_c   5.14
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg3Si
_chemical_formula_sum   'Mg3 Si1'
_cell_volume   79.82
_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  Mg0  1  0.0  0.0  0.51  1.0
  Mg  Mg1  1  0.0  0.44  0.32  1.0
  Mg  Mg2  1  0.59  0.0  0.02  1.0
  Si  Si3  1  0.59  0.44  0.72  1.0

Mg Mg Mg Si
Mg Mg Mg Si 0 1 o o - 0 1 o o o 0 1 + o - 0 1 + o o 0 2 o o o 0 2 + - o 0 2 + o o 0 0 + o o 0 3 o - - 0 3 o o - 1 3 - - o 1 3 - o o 1 3 o o o 1 1 + o o 1 2 o - o 1 2 o o o 2 3 - o o 2 3 o o o 3 3 + o o 
MgMg2Si crystallizes in the triclinic P1 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 1-coordinate geometry to four equivalent Mg(2) and two equivalent Si(1) atoms. There are a spread of Mg(1)-Mg(2) bond distances ranging from 2.83-3.23 Å. There is one shorter (2.67 Å) and one longer (3.15 Å) Mg(1)-Si(1) bond length. In the second Mg site, Mg(2) is bonded in a 11-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and three equivalent Si(1) atoms. Both Mg(2)-Mg(2) bond lengths are 3.18 Å. There is one shorter (2.37 Å) and one longer (2.91 Å) Mg(2)-Mg(3) bond length. There are a spread of Mg(2)-Si(1) bond distances ranging from 2.73-3.20 Å. In the third Mg site, Mg(3) is bonded in a 1-coordinate geometry to two equivalent Mg(2) and two equivalent Si(1) atoms. There is one shorter (2.43 Å) and one longer (2.78 Å) Mg(3)-Si(1) bond length. Si(1) is bonded in a 7-coordinate geometry to two equivalent Mg(1), two equivalent Mg(3), and three equivalent Mg(2) atoms.