The structure described by MgSi crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to three equivalent Si(3) and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and three equivalent Si(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to one Mg(2), two equivalent Mg(3), four equivalent Mg(1), and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to three equivalent Mg(3), four equivalent Mg(2), and two equivalent Si(2) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), three equivalent Mg(1), and three equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.310
_cell_length_b   5.439
_cell_length_c   9.505
_cell_angle_alpha   89.254
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   222.784
_cell_formula_units_Z   6
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  0.250  0.658  0.568  1.0
  Mg  Mg1  1  0.250  0.894  0.879  1.0
  Mg  Mg2  1  0.750  0.106  0.121  1.0
  Mg  Mg3  1  0.250  0.590  0.237  1.0
  Mg  Mg4  1  0.750  0.410  0.763  1.0
  Mg  Mg5  1  0.750  0.342  0.432  1.0
  Si  Si6  1  0.750  0.839  0.403  1.0
  Si  Si7  1  0.250  0.389  0.958  1.0
  Si  Si8  1  0.250  0.161  0.597  1.0
  Si  Si9  1  0.750  0.926  0.664  1.0
  Si  Si10  1  0.250  0.074  0.336  1.0
  Si  Si11  1  0.750  0.611  0.042  1.0
[/CIF]
.
The structure described by MgSi crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to three equivalent Si(3) and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and three equivalent Si(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to one Mg(2), two equivalent Mg(3), four equivalent Mg(1), and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to three equivalent Mg(3), four equivalent Mg(2), and two equivalent Si(2) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), three equivalent Mg(1), and three equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.310
_cell_length_b   5.439
_cell_length_c   9.505
_cell_angle_alpha   89.254
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   222.784
_cell_formula_units_Z   6
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  0.250  0.658  0.568  1.0
  Mg  Mg1  1  0.250  0.894  0.879  1.0
  Mg  Mg2  1  0.750  0.106  0.121  1.0
  Mg  Mg3  1  0.250  0.590  0.237  1.0
  Mg  Mg4  1  0.750  0.410  0.763  1.0
  Mg  Mg5  1  0.750  0.342  0.432  1.0
  Si  Si6  1  0.750  0.839  0.403  1.0
  Si  Si7  1  0.250  0.389  0.958  1.0
  Si  Si8  1  0.250  0.161  0.597  1.0
  Si  Si9  1  0.750  0.926  0.664  1.0
  Si  Si10  1  0.250  0.074  0.336  1.0
  Si  Si11  1  0.750  0.611  0.042  1.0
[/CIF]
.