The material described by Mg4Si3 crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(2) and two equivalent Si(3) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Si(2), two equivalent Si(1), and three equivalent Si(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(5), two equivalent Mg(4), three equivalent Mg(3), one Si(1), and one Si(3) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(3), one Mg(4), one Mg(5), three equivalent Mg(1), and one Si(2) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), one Mg(5), two equivalent Mg(3), three equivalent Mg(4), and one Si(1) atom. is represented by the CIF file [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.703
_cell_length_b   6.403
_cell_length_c   8.183
_cell_angle_alpha   68.996
_cell_angle_beta   80.342
_cell_angle_gamma   78.194
_symmetry_Int_Tables_number   1
_cell_volume   271.611
_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  0.854  0.497  0.165  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.604  0.819  0.676  1.0
  Mg  Mg3  1  0.396  0.181  0.324  1.0
  Mg  Mg4  1  0.146  0.503  0.835  1.0
  Mg  Mg5  1  0.251  0.658  0.408  1.0
  Mg  Mg6  1  0.749  0.342  0.592  1.0
  Mg  Mg7  1  0.000  0.000  0.000  1.0
  Si  Si8  1  0.934  0.064  0.357  1.0
  Si  Si9  1  0.335  0.593  0.081  1.0
  Si  Si10  1  0.066  0.936  0.643  1.0
  Si  Si11  1  0.713  0.792  0.333  1.0
  Si  Si12  1  0.665  0.407  0.919  1.0
  Si  Si13  1  0.287  0.208  0.667  1.0
[/CIF]
.
The material described by Mg4Si3 crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(2) and two equivalent Si(3) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Si(2), two equivalent Si(1), and three equivalent Si(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(5), two equivalent Mg(4), three equivalent Mg(3), one Si(1), and one Si(3) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(3), one Mg(4), one Mg(5), three equivalent Mg(1), and one Si(2) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), one Mg(5), two equivalent Mg(3), three equivalent Mg(4), and one Si(1) atom. is represented by the CIF file [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.703
_cell_length_b   6.403
_cell_length_c   8.183
_cell_angle_alpha   68.996
_cell_angle_beta   80.342
_cell_angle_gamma   78.194
_symmetry_Int_Tables_number   1
_cell_volume   271.611
_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  0.854  0.497  0.165  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.604  0.819  0.676  1.0
  Mg  Mg3  1  0.396  0.181  0.324  1.0
  Mg  Mg4  1  0.146  0.503  0.835  1.0
  Mg  Mg5  1  0.251  0.658  0.408  1.0
  Mg  Mg6  1  0.749  0.342  0.592  1.0
  Mg  Mg7  1  0.000  0.000  0.000  1.0
  Si  Si8  1  0.934  0.064  0.357  1.0
  Si  Si9  1  0.335  0.593  0.081  1.0
  Si  Si10  1  0.066  0.936  0.643  1.0
  Si  Si11  1  0.713  0.792  0.333  1.0
  Si  Si12  1  0.665  0.407  0.919  1.0
  Si  Si13  1  0.287  0.208  0.667  1.0
[/CIF]
.