The compound described by Mg2Si crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(1) and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to one Si(2) and three equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), three equivalent Mg(2), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), three equivalent Mg(1), and one Si(2) atom. is represented by the CIF card [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.747
_cell_length_b   5.869
_cell_length_c   7.997
_cell_angle_alpha   100.787
_cell_angle_beta   108.715
_cell_angle_gamma   102.640
_symmetry_Int_Tables_number   1
_cell_volume   239.409
_cell_formula_units_Z   4
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  0.397  0.752  0.549  1.0
  Mg  Mg1  1  0.452  0.626  0.166  1.0
  Mg  Mg2  1  0.075  0.639  0.784  1.0
  Mg  Mg3  1  0.603  0.248  0.451  1.0
  Mg  Mg4  1  0.548  0.374  0.834  1.0
  Mg  Mg5  1  0.925  0.361  0.216  1.0
  Mg  Mg6  1  0.034  0.870  0.188  1.0
  Mg  Mg7  1  0.966  0.130  0.812  1.0
  Si  Si8  1  0.398  0.121  0.074  1.0
  Si  Si9  1  0.126  0.209  0.518  1.0
  Si  Si10  1  0.874  0.791  0.482  1.0
  Si  Si11  1  0.602  0.879  0.926  1.0
[/CIF]
.
The compound described by Mg2Si crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(1) and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to one Si(2) and three equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), three equivalent Mg(2), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), three equivalent Mg(1), and one Si(2) atom. is represented by the CIF card [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.747
_cell_length_b   5.869
_cell_length_c   7.997
_cell_angle_alpha   100.787
_cell_angle_beta   108.715
_cell_angle_gamma   102.640
_symmetry_Int_Tables_number   1
_cell_volume   239.409
_cell_formula_units_Z   4
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  0.397  0.752  0.549  1.0
  Mg  Mg1  1  0.452  0.626  0.166  1.0
  Mg  Mg2  1  0.075  0.639  0.784  1.0
  Mg  Mg3  1  0.603  0.248  0.451  1.0
  Mg  Mg4  1  0.548  0.374  0.834  1.0
  Mg  Mg5  1  0.925  0.361  0.216  1.0
  Mg  Mg6  1  0.034  0.870  0.188  1.0
  Mg  Mg7  1  0.966  0.130  0.812  1.0
  Si  Si8  1  0.398  0.121  0.074  1.0
  Si  Si9  1  0.126  0.209  0.518  1.0
  Si  Si10  1  0.874  0.791  0.482  1.0
  Si  Si11  1  0.602  0.879  0.926  1.0
[/CIF]
.