The crystal structure described by Mg2Si is Cotunnite structured and crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. Si(1) is bonded in a 8-coordinate geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.263
_cell_length_b   4.955
_cell_length_c   6.789
_cell_angle_alpha   88.246
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   244.202
_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  0.600  0.180  0.693  1.0
  Mg  Mg1  1  0.286  0.342  0.001  1.0
  Mg  Mg2  1  0.400  0.820  0.307  1.0
  Mg  Mg3  1  0.786  0.658  0.499  1.0
  Mg  Mg4  1  0.714  0.658  0.999  1.0
  Mg  Mg5  1  0.100  0.820  0.807  1.0
  Mg  Mg6  1  0.214  0.342  0.501  1.0
  Mg  Mg7  1  0.900  0.180  0.193  1.0
  Si  Si8  1  0.948  0.301  0.780  1.0
  Si  Si9  1  0.552  0.301  0.280  1.0
  Si  Si10  1  0.052  0.699  0.220  1.0
  Si  Si11  1  0.448  0.699  0.720  1.0
[/CIF]
.
The crystal structure described by Mg2Si is Cotunnite structured and crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. Si(1) is bonded in a 8-coordinate geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.263
_cell_length_b   4.955
_cell_length_c   6.789
_cell_angle_alpha   88.246
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   244.202
_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  0.600  0.180  0.693  1.0
  Mg  Mg1  1  0.286  0.342  0.001  1.0
  Mg  Mg2  1  0.400  0.820  0.307  1.0
  Mg  Mg3  1  0.786  0.658  0.499  1.0
  Mg  Mg4  1  0.714  0.658  0.999  1.0
  Mg  Mg5  1  0.100  0.820  0.807  1.0
  Mg  Mg6  1  0.214  0.342  0.501  1.0
  Mg  Mg7  1  0.900  0.180  0.193  1.0
  Si  Si8  1  0.948  0.301  0.780  1.0
  Si  Si9  1  0.552  0.301  0.280  1.0
  Si  Si10  1  0.052  0.699  0.220  1.0
  Si  Si11  1  0.448  0.699  0.720  1.0
[/CIF]
.