The material described by MgSi crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(4) and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(6), three equivalent Si(2), and three equivalent Si(4) atoms. In the third Mg site, Mg(3) is bonded in a 9-coordinate geometry to one Si(4), two equivalent Si(5), three equivalent Si(2), and three equivalent Si(6) atoms. In the fourth Mg site, Mg(4) is bonded in a 3-coordinate geometry to one Si(2), two equivalent Si(6), and three equivalent Si(5) atoms. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the sixth Mg site, Mg(6) is bonded in a 6-coordinate geometry to one Si(5), two equivalent Si(3), and three equivalent Si(1) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 1-coordinate geometry to three equivalent Mg(6), one Si(3), and two equivalent Si(5) atoms. In the second Si site, Si(2) is bonded to one Mg(4), one Mg(5), three equivalent Mg(2), three equivalent Mg(3), two equivalent Si(4), and two equivalent Si(6) atoms to form a mixture of distorted edge and face-sharing SiMg8Si4 cuboctahedra. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Mg(5), two equivalent Mg(6), three equivalent Mg(1), and one Si(1) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(5), three equivalent Mg(2), and two equivalent Si(2) atoms. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(6), two equivalent Mg(3), three equivalent Mg(4), one Si(6), and two equivalent Si(1) atoms. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(4), three equivalent Mg(3), one Si(5), and two equivalent Si(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.112
_cell_length_b   5.112
_cell_length_c   12.410
_cell_angle_alpha   71.655
_cell_angle_beta   71.655
_cell_angle_gamma   47.407
_symmetry_Int_Tables_number   1
_cell_volume   224.197
_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  0.579  0.579  0.926  1.0
  Mg  Mg1  1  0.078  0.078  0.187  1.0
  Mg  Mg2  1  0.382  0.382  0.401  1.0
  Mg  Mg3  1  0.592  0.592  0.563  1.0
  Mg  Mg4  1  0.823  0.823  0.048  1.0
  Mg  Mg5  1  0.948  0.948  0.781  1.0
  Si  Si6  1  0.256  0.256  0.716  1.0
  Si  Si7  1  0.735  0.735  0.291  1.0
  Si  Si8  1  0.283  0.283  0.911  1.0
  Si  Si9  1  0.394  0.394  0.167  1.0
  Si  Si10  1  0.859  0.859  0.593  1.0
  Si  Si11  1  0.082  0.082  0.417  1.0
[/CIF]
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The material described by MgSi crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(4) and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(6), three equivalent Si(2), and three equivalent Si(4) atoms. In the third Mg site, Mg(3) is bonded in a 9-coordinate geometry to one Si(4), two equivalent Si(5), three equivalent Si(2), and three equivalent Si(6) atoms. In the fourth Mg site, Mg(4) is bonded in a 3-coordinate geometry to one Si(2), two equivalent Si(6), and three equivalent Si(5) atoms. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the sixth Mg site, Mg(6) is bonded in a 6-coordinate geometry to one Si(5), two equivalent Si(3), and three equivalent Si(1) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 1-coordinate geometry to three equivalent Mg(6), one Si(3), and two equivalent Si(5) atoms. In the second Si site, Si(2) is bonded to one Mg(4), one Mg(5), three equivalent Mg(2), three equivalent Mg(3), two equivalent Si(4), and two equivalent Si(6) atoms to form a mixture of distorted edge and face-sharing SiMg8Si4 cuboctahedra. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Mg(5), two equivalent Mg(6), three equivalent Mg(1), and one Si(1) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(5), three equivalent Mg(2), and two equivalent Si(2) atoms. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(6), two equivalent Mg(3), three equivalent Mg(4), one Si(6), and two equivalent Si(1) atoms. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(4), three equivalent Mg(3), one Si(5), and two equivalent Si(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.112
_cell_length_b   5.112
_cell_length_c   12.410
_cell_angle_alpha   71.655
_cell_angle_beta   71.655
_cell_angle_gamma   47.407
_symmetry_Int_Tables_number   1
_cell_volume   224.197
_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  0.579  0.579  0.926  1.0
  Mg  Mg1  1  0.078  0.078  0.187  1.0
  Mg  Mg2  1  0.382  0.382  0.401  1.0
  Mg  Mg3  1  0.592  0.592  0.563  1.0
  Mg  Mg4  1  0.823  0.823  0.048  1.0
  Mg  Mg5  1  0.948  0.948  0.781  1.0
  Si  Si6  1  0.256  0.256  0.716  1.0
  Si  Si7  1  0.735  0.735  0.291  1.0
  Si  Si8  1  0.283  0.283  0.911  1.0
  Si  Si9  1  0.394  0.394  0.167  1.0
  Si  Si10  1  0.859  0.859  0.593  1.0
  Si  Si11  1  0.082  0.082  0.417  1.0
[/CIF]
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