The material described by Mg2Si crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Si(1) and two equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(2) and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), and three equivalent Mg(3) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), two equivalent Mg(2), and one Si(2) atom. is represented by the CIF file [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.161
_cell_length_b   6.593
_cell_length_c   7.721
_cell_angle_alpha   108.195
_cell_angle_beta   100.868
_cell_angle_gamma   97.974
_symmetry_Int_Tables_number   1
_cell_volume   239.527
_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  0.119  0.604  0.248  1.0
  Mg  Mg1  1  0.241  0.921  0.048  1.0
  Mg  Mg2  1  0.881  0.396  0.752  1.0
  Mg  Mg3  1  0.617  0.398  0.334  1.0
  Mg  Mg4  1  0.291  0.065  0.597  1.0
  Mg  Mg5  1  0.759  0.079  0.952  1.0
  Mg  Mg6  1  0.709  0.935  0.403  1.0
  Mg  Mg7  1  0.383  0.602  0.666  1.0
  Si  Si8  1  0.918  0.768  0.671  1.0
  Si  Si9  1  0.082  0.232  0.329  1.0
  Si  Si10  1  0.348  0.325  0.948  1.0
  Si  Si11  1  0.652  0.675  0.052  1.0
[/CIF]
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The material described by Mg2Si crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Si(1) and two equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(2) and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), and three equivalent Mg(3) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), two equivalent Mg(2), and one Si(2) atom. is represented by the CIF file [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.161
_cell_length_b   6.593
_cell_length_c   7.721
_cell_angle_alpha   108.195
_cell_angle_beta   100.868
_cell_angle_gamma   97.974
_symmetry_Int_Tables_number   1
_cell_volume   239.527
_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  0.119  0.604  0.248  1.0
  Mg  Mg1  1  0.241  0.921  0.048  1.0
  Mg  Mg2  1  0.881  0.396  0.752  1.0
  Mg  Mg3  1  0.617  0.398  0.334  1.0
  Mg  Mg4  1  0.291  0.065  0.597  1.0
  Mg  Mg5  1  0.759  0.079  0.952  1.0
  Mg  Mg6  1  0.709  0.935  0.403  1.0
  Mg  Mg7  1  0.383  0.602  0.666  1.0
  Si  Si8  1  0.918  0.768  0.671  1.0
  Si  Si9  1  0.082  0.232  0.329  1.0
  Si  Si10  1  0.348  0.325  0.948  1.0
  Si  Si11  1  0.652  0.675  0.052  1.0
[/CIF]
.