The material structure described by Mg2Si crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to two equivalent Si(2) and three equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Si(2) and three equivalent Si(1) 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. In the fifth Mg site, Mg(5) is bonded in a distorted linear 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 11-coordinate geometry to one Mg(4), one Mg(5), two equivalent Mg(2), three equivalent Mg(1), three equivalent Mg(3), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(4), one Mg(5), two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms. is represented by the CIF file [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.112
_cell_length_b   6.112
_cell_length_c   7.989
_cell_angle_alpha   105.748
_cell_angle_beta   99.167
_cell_angle_gamma   95.734
_symmetry_Int_Tables_number   1
_cell_volume   234.491
_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  0.049  0.746  0.987  1.0
  Mg  Mg1  1  0.985  0.149  0.350  1.0
  Mg  Mg2  1  0.431  0.341  0.826  1.0
  Mg  Mg3  1  0.015  0.851  0.650  1.0
  Mg  Mg4  1  0.951  0.254  0.013  1.0
  Mg  Mg5  1  0.500  0.500  0.500  1.0
  Mg  Mg6  1  0.500  0.000  0.500  1.0
  Mg  Mg7  1  0.569  0.659  0.174  1.0
  Si  Si8  1  0.454  0.154  0.133  1.0
  Si  Si9  1  0.546  0.846  0.867  1.0
  Si  Si10  1  0.091  0.664  0.310  1.0
  Si  Si11  1  0.909  0.336  0.690  1.0
[/CIF]
.
The material structure described by Mg2Si crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to two equivalent Si(2) and three equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Si(2) and three equivalent Si(1) 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. In the fifth Mg site, Mg(5) is bonded in a distorted linear 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 11-coordinate geometry to one Mg(4), one Mg(5), two equivalent Mg(2), three equivalent Mg(1), three equivalent Mg(3), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(4), one Mg(5), two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms. is represented by the CIF file [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.112
_cell_length_b   6.112
_cell_length_c   7.989
_cell_angle_alpha   105.748
_cell_angle_beta   99.167
_cell_angle_gamma   95.734
_symmetry_Int_Tables_number   1
_cell_volume   234.491
_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  0.049  0.746  0.987  1.0
  Mg  Mg1  1  0.985  0.149  0.350  1.0
  Mg  Mg2  1  0.431  0.341  0.826  1.0
  Mg  Mg3  1  0.015  0.851  0.650  1.0
  Mg  Mg4  1  0.951  0.254  0.013  1.0
  Mg  Mg5  1  0.500  0.500  0.500  1.0
  Mg  Mg6  1  0.500  0.000  0.500  1.0
  Mg  Mg7  1  0.569  0.659  0.174  1.0
  Si  Si8  1  0.454  0.154  0.133  1.0
  Si  Si9  1  0.546  0.846  0.867  1.0
  Si  Si10  1  0.091  0.664  0.310  1.0
  Si  Si11  1  0.909  0.336  0.690  1.0
[/CIF]
.