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 5-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(1) and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(3), four equivalent Mg(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), three equivalent Mg(4), and one Si(1) atom. is represented by the CIF file [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.203
_cell_length_b   5.507
_cell_length_c   8.462
_cell_angle_alpha   81.216
_cell_angle_beta   81.500
_cell_angle_gamma   86.760
_symmetry_Int_Tables_number   1
_cell_volume   236.837
_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  0.719  0.553  0.611  1.0
  Mg  Mg1  1  0.335  0.763  0.992  1.0
  Mg  Mg2  1  0.816  0.681  0.221  1.0
  Mg  Mg3  1  0.211  0.872  0.611  1.0
  Mg  Mg4  1  0.184  0.319  0.779  1.0
  Mg  Mg5  1  0.789  0.128  0.389  1.0
  Mg  Mg6  1  0.281  0.447  0.389  1.0
  Mg  Mg7  1  0.665  0.237  0.008  1.0
  Si  Si8  1  0.864  0.722  0.891  1.0
  Si  Si9  1  0.136  0.278  0.109  1.0
  Si  Si10  1  0.342  0.958  0.284  1.0
  Si  Si11  1  0.658  0.042  0.716  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 5-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(1) and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(3), four equivalent Mg(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), three equivalent Mg(4), and one Si(1) atom. is represented by the CIF file [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.203
_cell_length_b   5.507
_cell_length_c   8.462
_cell_angle_alpha   81.216
_cell_angle_beta   81.500
_cell_angle_gamma   86.760
_symmetry_Int_Tables_number   1
_cell_volume   236.837
_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  0.719  0.553  0.611  1.0
  Mg  Mg1  1  0.335  0.763  0.992  1.0
  Mg  Mg2  1  0.816  0.681  0.221  1.0
  Mg  Mg3  1  0.211  0.872  0.611  1.0
  Mg  Mg4  1  0.184  0.319  0.779  1.0
  Mg  Mg5  1  0.789  0.128  0.389  1.0
  Mg  Mg6  1  0.281  0.447  0.389  1.0
  Mg  Mg7  1  0.665  0.237  0.008  1.0
  Si  Si8  1  0.864  0.722  0.891  1.0
  Si  Si9  1  0.136  0.278  0.109  1.0
  Si  Si10  1  0.342  0.958  0.284  1.0
  Si  Si11  1  0.658  0.042  0.716  1.0
[/CIF]
.