The compound described by MgSi2 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded in a 7-coordinate geometry to three equivalent Si(2) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to four equivalent Mg(1) and three equivalent Si(1) atoms. In the second Si site, Si(2) is bonded to three equivalent Mg(1) and three equivalent Si(2) atoms to form distorted edge-sharing SiMg3Si3 octahedra. is represented by the CIF file [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.732
_cell_length_b   3.732
_cell_length_c   9.834
_cell_angle_alpha   79.433
_cell_angle_beta   90.000
_cell_angle_gamma   119.995
_symmetry_Int_Tables_number   1
_cell_volume   115.943
_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  0.084  0.167  0.750  1.0
  Mg  Mg1  1  0.916  0.833  0.250  1.0
  Si  Si2  1  0.816  0.633  0.553  1.0
  Si  Si3  1  0.350  0.701  0.948  1.0
  Si  Si4  1  0.650  0.299  0.052  1.0
  Si  Si5  1  0.184  0.367  0.447  1.0
[/CIF]
.
The compound described by MgSi2 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded in a 7-coordinate geometry to three equivalent Si(2) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to four equivalent Mg(1) and three equivalent Si(1) atoms. In the second Si site, Si(2) is bonded to three equivalent Mg(1) and three equivalent Si(2) atoms to form distorted edge-sharing SiMg3Si3 octahedra. is represented by the CIF file [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.732
_cell_length_b   3.732
_cell_length_c   9.834
_cell_angle_alpha   79.433
_cell_angle_beta   90.000
_cell_angle_gamma   119.995
_symmetry_Int_Tables_number   1
_cell_volume   115.943
_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  0.084  0.167  0.750  1.0
  Mg  Mg1  1  0.916  0.833  0.250  1.0
  Si  Si2  1  0.816  0.633  0.553  1.0
  Si  Si3  1  0.350  0.701  0.948  1.0
  Si  Si4  1  0.650  0.299  0.052  1.0
  Si  Si5  1  0.184  0.367  0.447  1.0
[/CIF]
.