The compound described by MgSi2 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to two equivalent Mg(2), one Si(2), one Si(4), three equivalent Si(1), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to two equivalent Mg(1), two equivalent Si(2), and four equivalent Si(4) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(2), and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 6-coordinate geometry to one Mg(1), two equivalent Mg(2), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(3), and three equivalent Si(1) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(4), and two equivalent Si(2) atoms. is represented by the CIF card [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.730
_cell_length_b   5.397
_cell_length_c   11.932
_cell_angle_alpha   84.819
_cell_angle_beta   81.820
_cell_angle_gamma   70.064
_symmetry_Int_Tables_number   1
_cell_volume   223.325
_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  0.699  0.919  0.820  1.0
  Mg  Mg1  1  0.301  0.081  0.180  1.0
  Mg  Mg2  1  0.811  0.945  0.391  1.0
  Mg  Mg3  1  0.189  0.055  0.609  1.0
  Si  Si4  1  0.598  0.519  0.113  1.0
  Si  Si5  1  0.402  0.481  0.887  1.0
  Si  Si6  1  0.451  0.442  0.689  1.0
  Si  Si7  1  0.549  0.558  0.311  1.0
  Si  Si8  1  0.988  0.222  0.963  1.0
  Si  Si9  1  0.012  0.778  0.037  1.0
  Si  Si10  1  0.099  0.366  0.413  1.0
  Si  Si11  1  0.901  0.634  0.587  1.0
[/CIF]
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The compound described by MgSi2 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to two equivalent Mg(2), one Si(2), one Si(4), three equivalent Si(1), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to two equivalent Mg(1), two equivalent Si(2), and four equivalent Si(4) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(2), and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 6-coordinate geometry to one Mg(1), two equivalent Mg(2), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(3), and three equivalent Si(1) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(4), and two equivalent Si(2) atoms. is represented by the CIF card [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.730
_cell_length_b   5.397
_cell_length_c   11.932
_cell_angle_alpha   84.819
_cell_angle_beta   81.820
_cell_angle_gamma   70.064
_symmetry_Int_Tables_number   1
_cell_volume   223.325
_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  0.699  0.919  0.820  1.0
  Mg  Mg1  1  0.301  0.081  0.180  1.0
  Mg  Mg2  1  0.811  0.945  0.391  1.0
  Mg  Mg3  1  0.189  0.055  0.609  1.0
  Si  Si4  1  0.598  0.519  0.113  1.0
  Si  Si5  1  0.402  0.481  0.887  1.0
  Si  Si6  1  0.451  0.442  0.689  1.0
  Si  Si7  1  0.549  0.558  0.311  1.0
  Si  Si8  1  0.988  0.222  0.963  1.0
  Si  Si9  1  0.012  0.778  0.037  1.0
  Si  Si10  1  0.099  0.366  0.413  1.0
  Si  Si11  1  0.901  0.634  0.587  1.0
[/CIF]
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