The crystal structure 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 6-coordinate geometry to one Si(1), one Si(3), two equivalent Si(4), and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Si(1), three equivalent Si(3), and three 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 one Mg(1), two equivalent Mg(2), one Si(3), and three equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(4), and three equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to one Mg(1), three equivalent Mg(2), one Si(1), two equivalent Si(3), and three equivalent Si(4) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Mg(1), three equivalent Mg(2), one Si(2), and three equivalent Si(3) atoms. is represented by the CIF card [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.828
_cell_length_b   6.408
_cell_length_c   9.250
_cell_angle_alpha   76.700
_cell_angle_beta   89.031
_cell_angle_gamma   89.539
_symmetry_Int_Tables_number   1
_cell_volume   220.771
_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  0.244  0.004  0.852  1.0
  Mg  Mg1  1  0.756  0.996  0.148  1.0
  Mg  Mg2  1  0.256  0.208  0.374  1.0
  Mg  Mg3  1  0.744  0.792  0.626  1.0
  Si  Si4  1  0.764  0.431  0.156  1.0
  Si  Si5  1  0.738  0.330  0.891  1.0
  Si  Si6  1  0.245  0.450  0.601  1.0
  Si  Si7  1  0.254  0.794  0.369  1.0
  Si  Si8  1  0.236  0.569  0.844  1.0
  Si  Si9  1  0.262  0.670  0.109  1.0
  Si  Si10  1  0.755  0.550  0.399  1.0
  Si  Si11  1  0.746  0.206  0.631  1.0
[/CIF]
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The crystal structure 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 6-coordinate geometry to one Si(1), one Si(3), two equivalent Si(4), and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Si(1), three equivalent Si(3), and three 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 one Mg(1), two equivalent Mg(2), one Si(3), and three equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(4), and three equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to one Mg(1), three equivalent Mg(2), one Si(1), two equivalent Si(3), and three equivalent Si(4) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Mg(1), three equivalent Mg(2), one Si(2), and three equivalent Si(3) atoms. is represented by the CIF card [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.828
_cell_length_b   6.408
_cell_length_c   9.250
_cell_angle_alpha   76.700
_cell_angle_beta   89.031
_cell_angle_gamma   89.539
_symmetry_Int_Tables_number   1
_cell_volume   220.771
_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  0.244  0.004  0.852  1.0
  Mg  Mg1  1  0.756  0.996  0.148  1.0
  Mg  Mg2  1  0.256  0.208  0.374  1.0
  Mg  Mg3  1  0.744  0.792  0.626  1.0
  Si  Si4  1  0.764  0.431  0.156  1.0
  Si  Si5  1  0.738  0.330  0.891  1.0
  Si  Si6  1  0.245  0.450  0.601  1.0
  Si  Si7  1  0.254  0.794  0.369  1.0
  Si  Si8  1  0.236  0.569  0.844  1.0
  Si  Si9  1  0.262  0.670  0.109  1.0
  Si  Si10  1  0.755  0.550  0.399  1.0
  Si  Si11  1  0.746  0.206  0.631  1.0
[/CIF]
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