The material structure 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 3-coordinate geometry to one Si(1) and two equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Si(2) and three equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(1) and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(3), three equivalent Mg(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(1), three equivalent Mg(4), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.425
_cell_length_b   6.264
_cell_length_c   7.688
_cell_angle_alpha   88.594
_cell_angle_beta   70.612
_cell_angle_gamma   89.253
_symmetry_Int_Tables_number   1
_cell_volume   246.374
_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  0.229  0.631  0.517  1.0
  Mg  Mg1  1  0.799  0.876  0.918  1.0
  Mg  Mg2  1  0.771  0.875  0.446  1.0
  Mg  Mg3  1  0.806  0.377  0.878  1.0
  Mg  Mg4  1  0.229  0.125  0.554  1.0
  Mg  Mg5  1  0.201  0.124  0.082  1.0
  Mg  Mg6  1  0.194  0.623  0.122  1.0
  Mg  Mg7  1  0.771  0.369  0.483  1.0
  Si  Si8  1  0.628  0.174  0.215  1.0
  Si  Si9  1  0.351  0.428  0.790  1.0
  Si  Si10  1  0.372  0.826  0.785  1.0
  Si  Si11  1  0.649  0.572  0.210  1.0
[/CIF]
.
The material structure 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 3-coordinate geometry to one Si(1) and two equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Si(2) and three equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(1) and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(3), three equivalent Mg(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(1), three equivalent Mg(4), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.425
_cell_length_b   6.264
_cell_length_c   7.688
_cell_angle_alpha   88.594
_cell_angle_beta   70.612
_cell_angle_gamma   89.253
_symmetry_Int_Tables_number   1
_cell_volume   246.374
_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  0.229  0.631  0.517  1.0
  Mg  Mg1  1  0.799  0.876  0.918  1.0
  Mg  Mg2  1  0.771  0.875  0.446  1.0
  Mg  Mg3  1  0.806  0.377  0.878  1.0
  Mg  Mg4  1  0.229  0.125  0.554  1.0
  Mg  Mg5  1  0.201  0.124  0.082  1.0
  Mg  Mg6  1  0.194  0.623  0.122  1.0
  Mg  Mg7  1  0.771  0.369  0.483  1.0
  Si  Si8  1  0.628  0.174  0.215  1.0
  Si  Si9  1  0.351  0.428  0.790  1.0
  Si  Si10  1  0.372  0.826  0.785  1.0
  Si  Si11  1  0.649  0.572  0.210  1.0
[/CIF]
.