The compound described by MgSi2 crystallizes in the monoclinic P2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Mg(2), one Si(3), two equivalent Si(2), two equivalent Si(4), two equivalent Si(5), and three equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to two equivalent Mg(1), two equivalent Si(1), two equivalent Si(4), and four equivalent Si(3) atoms. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to two equivalent Mg(2), three equivalent Mg(1), two equivalent Si(2), two equivalent Si(4), and two equivalent Si(5) atoms. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(3), and two equivalent Si(4) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), one Si(5), two equivalent Si(1), and two equivalent Si(3) atoms. In the fifth Si site, Si(5) is bonded in a distorted square co-planar geometry to four equivalent Mg(1), two equivalent Si(4), and four equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.712
_cell_length_b   5.808
_cell_length_c   9.349
_cell_angle_alpha   87.405
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   201.352
_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  0.000  0.253  0.843  1.0
  Mg  Mg1  1  0.000  0.747  0.157  1.0
  Mg  Mg2  1  0.500  0.463  0.345  1.0
  Mg  Mg3  1  0.500  0.537  0.655  1.0
  Si  Si4  1  0.000  0.249  0.145  1.0
  Si  Si5  1  0.500  0.500  0.000  1.0
  Si  Si6  1  0.000  0.806  0.456  1.0
  Si  Si7  1  0.500  0.003  0.304  1.0
  Si  Si8  1  0.000  0.751  0.855  1.0
  Si  Si9  1  0.500  0.000  0.000  1.0
  Si  Si10  1  0.000  0.194  0.544  1.0
  Si  Si11  1  0.500  0.997  0.696  1.0
[/CIF]
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The compound described by MgSi2 crystallizes in the monoclinic P2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Mg(2), one Si(3), two equivalent Si(2), two equivalent Si(4), two equivalent Si(5), and three equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to two equivalent Mg(1), two equivalent Si(1), two equivalent Si(4), and four equivalent Si(3) atoms. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to two equivalent Mg(2), three equivalent Mg(1), two equivalent Si(2), two equivalent Si(4), and two equivalent Si(5) atoms. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(3), and two equivalent Si(4) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), one Si(5), two equivalent Si(1), and two equivalent Si(3) atoms. In the fifth Si site, Si(5) is bonded in a distorted square co-planar geometry to four equivalent Mg(1), two equivalent Si(4), and four equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.712
_cell_length_b   5.808
_cell_length_c   9.349
_cell_angle_alpha   87.405
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   201.352
_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  0.000  0.253  0.843  1.0
  Mg  Mg1  1  0.000  0.747  0.157  1.0
  Mg  Mg2  1  0.500  0.463  0.345  1.0
  Mg  Mg3  1  0.500  0.537  0.655  1.0
  Si  Si4  1  0.000  0.249  0.145  1.0
  Si  Si5  1  0.500  0.500  0.000  1.0
  Si  Si6  1  0.000  0.806  0.456  1.0
  Si  Si7  1  0.500  0.003  0.304  1.0
  Si  Si8  1  0.000  0.751  0.855  1.0
  Si  Si9  1  0.500  0.000  0.000  1.0
  Si  Si10  1  0.000  0.194  0.544  1.0
  Si  Si11  1  0.500  0.997  0.696  1.0
[/CIF]
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