The crystal structure described by Mg2Si crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to six equivalent Mg(2) and five equivalent Si(1) atoms to form a mixture of distorted corner and face-sharing MgMg6Si5 trigonal bipyramids. In the second Mg site, Mg(2) is bonded in a 14-coordinate geometry to two equivalent Mg(2), six equivalent Mg(1), and six equivalent Si(1) atoms. Si(1) is bonded in a 11-coordinate geometry to five equivalent Mg(1) and six 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   4.625
_cell_length_b   4.625
_cell_length_c   6.084
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   112.692
_cell_formula_units_Z   2
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  0.667  0.333  0.250  1.0
  Mg  Mg1  1  0.333  0.667  0.750  1.0
  Mg  Mg2  1  0.000  0.000  0.500  1.0
  Mg  Mg3  1  0.000  0.000  0.000  1.0
  Si  Si4  1  0.667  0.333  0.750  1.0
  Si  Si5  1  0.333  0.667  0.250  1.0
[/CIF]
.
The crystal structure described by Mg2Si crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to six equivalent Mg(2) and five equivalent Si(1) atoms to form a mixture of distorted corner and face-sharing MgMg6Si5 trigonal bipyramids. In the second Mg site, Mg(2) is bonded in a 14-coordinate geometry to two equivalent Mg(2), six equivalent Mg(1), and six equivalent Si(1) atoms. Si(1) is bonded in a 11-coordinate geometry to five equivalent Mg(1) and six 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   4.625
_cell_length_b   4.625
_cell_length_c   6.084
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   112.692
_cell_formula_units_Z   2
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  0.667  0.333  0.250  1.0
  Mg  Mg1  1  0.333  0.667  0.750  1.0
  Mg  Mg2  1  0.000  0.000  0.500  1.0
  Mg  Mg3  1  0.000  0.000  0.000  1.0
  Si  Si4  1  0.667  0.333  0.750  1.0
  Si  Si5  1  0.333  0.667  0.250  1.0
[/CIF]
.