The compound described by MgSi2 is Magnesium tetraboride-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to two equivalent Mg(2), one Si(2), one Si(4), three equivalent Si(1), and four equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 5-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 8-coordinate geometry to four equivalent Mg(1), one Si(3), and three equivalent Si(1) atoms. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(4), and two equivalent Si(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.397
_cell_length_b   5.397
_cell_length_c   12.354
_cell_angle_alpha   72.214
_cell_angle_beta   72.214
_cell_angle_gamma   41.280
_symmetry_Int_Tables_number   1
_cell_volume   224.444
_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  0.370  0.370  0.170  1.0
  Mg  Mg1  1  0.630  0.630  0.830  1.0
  Mg  Mg2  1  0.179  0.179  0.612  1.0
  Mg  Mg3  1  0.821  0.821  0.388  1.0
  Si  Si4  1  0.320  0.320  0.881  1.0
  Si  Si5  1  0.680  0.680  0.119  1.0
  Si  Si6  1  0.545  0.545  0.316  1.0
  Si  Si7  1  0.455  0.455  0.684  1.0
  Si  Si8  1  0.093  0.093  0.039  1.0
  Si  Si9  1  0.907  0.907  0.961  1.0
  Si  Si10  1  0.896  0.896  0.587  1.0
  Si  Si11  1  0.104  0.104  0.413  1.0
[/CIF]
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The compound described by MgSi2 is Magnesium tetraboride-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to two equivalent Mg(2), one Si(2), one Si(4), three equivalent Si(1), and four equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 5-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 8-coordinate geometry to four equivalent Mg(1), one Si(3), and three equivalent Si(1) atoms. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(4), and two equivalent Si(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.397
_cell_length_b   5.397
_cell_length_c   12.354
_cell_angle_alpha   72.214
_cell_angle_beta   72.214
_cell_angle_gamma   41.280
_symmetry_Int_Tables_number   1
_cell_volume   224.444
_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  0.370  0.370  0.170  1.0
  Mg  Mg1  1  0.630  0.630  0.830  1.0
  Mg  Mg2  1  0.179  0.179  0.612  1.0
  Mg  Mg3  1  0.821  0.821  0.388  1.0
  Si  Si4  1  0.320  0.320  0.881  1.0
  Si  Si5  1  0.680  0.680  0.119  1.0
  Si  Si6  1  0.545  0.545  0.316  1.0
  Si  Si7  1  0.455  0.455  0.684  1.0
  Si  Si8  1  0.093  0.093  0.039  1.0
  Si  Si9  1  0.907  0.907  0.961  1.0
  Si  Si10  1  0.896  0.896  0.587  1.0
  Si  Si11  1  0.104  0.104  0.413  1.0
[/CIF]
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