The structure described by Mg3Si2 crystallizes in the monoclinic C2/m space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 2-coordinate geometry to one Mg(3), 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 Mg(3), one Si(2), and three equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 11-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(3), three equivalent 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), three equivalent Mg(2), three equivalent Mg(3), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), two equivalent Mg(1), three equivalent Mg(3), and two equivalent Si(1) atoms. is represented by the CIF file [CIF]
data_Mg3Si2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.952
_cell_length_b   7.952
_cell_length_c   7.037
_cell_angle_alpha   84.400
_cell_angle_beta   84.400
_cell_angle_gamma   26.723
_symmetry_Int_Tables_number   1
_cell_volume   199.057
_cell_formula_units_Z   2
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  0.500  0.500  0.269  1.0
  Mg  Mg1  1  0.500  0.500  0.731  1.0
  Mg  Mg2  1  0.124  0.124  0.973  1.0
  Mg  Mg3  1  0.876  0.876  0.027  1.0
  Mg  Mg4  1  0.693  0.693  0.635  1.0
  Mg  Mg5  1  0.307  0.307  0.365  1.0
  Si  Si6  1  0.699  0.699  0.215  1.0
  Si  Si7  1  0.301  0.301  0.785  1.0
  Si  Si8  1  0.119  0.119  0.389  1.0
  Si  Si9  1  0.881  0.881  0.611  1.0
[/CIF]
.
The structure described by Mg3Si2 crystallizes in the monoclinic C2/m space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 2-coordinate geometry to one Mg(3), 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 Mg(3), one Si(2), and three equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 11-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(3), three equivalent 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), three equivalent Mg(2), three equivalent Mg(3), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), two equivalent Mg(1), three equivalent Mg(3), and two equivalent Si(1) atoms. is represented by the CIF file [CIF]
data_Mg3Si2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.952
_cell_length_b   7.952
_cell_length_c   7.037
_cell_angle_alpha   84.400
_cell_angle_beta   84.400
_cell_angle_gamma   26.723
_symmetry_Int_Tables_number   1
_cell_volume   199.057
_cell_formula_units_Z   2
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  0.500  0.500  0.269  1.0
  Mg  Mg1  1  0.500  0.500  0.731  1.0
  Mg  Mg2  1  0.124  0.124  0.973  1.0
  Mg  Mg3  1  0.876  0.876  0.027  1.0
  Mg  Mg4  1  0.693  0.693  0.635  1.0
  Mg  Mg5  1  0.307  0.307  0.365  1.0
  Si  Si6  1  0.699  0.699  0.215  1.0
  Si  Si7  1  0.301  0.301  0.785  1.0
  Si  Si8  1  0.119  0.119  0.389  1.0
  Si  Si9  1  0.881  0.881  0.611  1.0
[/CIF]
.