The structure described by Mg4Si3 crystallizes in the triclinic P1 space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Mg(6), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(6), one Si(1), one Si(2), one Si(4), and one Si(6) atom. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(4), one Si(5), and two equivalent Si(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Mg(6), one Si(1), one Si(2), one Si(3), and one Si(4) atom. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to one Si(3), one Si(4), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(2), one Si(1), one Si(2), one Si(5), and two equivalent Si(6) atoms. In the seventh Mg site, Mg(7) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(4) atoms. In the eighth Mg site, Mg(8) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(5) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to one Mg(2), one Mg(4), one Mg(6), one Si(2), one Si(5), and one Si(6) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(2), one Mg(4), one Mg(6), one Mg(7), one Mg(8), one Si(1), and one Si(5) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), one Mg(5), one Mg(7), one Mg(8), two equivalent Mg(3), and one Si(6) atom. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), and two equivalent Mg(7) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), one Mg(6), two equivalent Mg(8), one Si(1), one Si(2), and one Si(6) atom. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(5), two equivalent Mg(6), one Si(1), one Si(3), and one Si(5) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.090
_cell_length_b   10.261
_cell_length_c   7.123
_cell_angle_alpha   124.629
_cell_angle_beta   106.742
_cell_angle_gamma   90.067
_symmetry_Int_Tables_number   1
_cell_volume   286.659
_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  0.441  0.781  0.567  1.0
  Mg  Mg1  1  0.947  0.221  0.036  1.0
  Mg  Mg2  1  0.249  0.639  0.016  1.0
  Mg  Mg3  1  0.444  0.403  0.536  1.0
  Mg  Mg4  1  0.938  0.585  0.535  1.0
  Mg  Mg5  1  0.470  0.066  0.074  1.0
  Mg  Mg6  1  0.782  0.491  0.044  1.0
  Mg  Mg7  1  0.890  0.888  0.454  1.0
  Si  Si8  1  0.015  0.179  0.403  1.0
  Si  Si9  1  0.702  0.188  0.607  1.0
  Si  Si10  1  0.705  0.706  0.927  1.0
  Si  Si11  1  0.388  0.464  0.209  1.0
  Si  Si12  1  0.327  0.955  0.355  1.0
  Si  Si13  1  0.953  0.935  0.987  1.0
[/CIF]
.
The structure described by Mg4Si3 crystallizes in the triclinic P1 space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Mg(6), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(6), one Si(1), one Si(2), one Si(4), and one Si(6) atom. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(4), one Si(5), and two equivalent Si(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Mg(6), one Si(1), one Si(2), one Si(3), and one Si(4) atom. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to one Si(3), one Si(4), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(2), one Si(1), one Si(2), one Si(5), and two equivalent Si(6) atoms. In the seventh Mg site, Mg(7) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(4) atoms. In the eighth Mg site, Mg(8) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(5) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to one Mg(2), one Mg(4), one Mg(6), one Si(2), one Si(5), and one Si(6) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(2), one Mg(4), one Mg(6), one Mg(7), one Mg(8), one Si(1), and one Si(5) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), one Mg(5), one Mg(7), one Mg(8), two equivalent Mg(3), and one Si(6) atom. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), and two equivalent Mg(7) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), one Mg(6), two equivalent Mg(8), one Si(1), one Si(2), and one Si(6) atom. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(5), two equivalent Mg(6), one Si(1), one Si(3), and one Si(5) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.090
_cell_length_b   10.261
_cell_length_c   7.123
_cell_angle_alpha   124.629
_cell_angle_beta   106.742
_cell_angle_gamma   90.067
_symmetry_Int_Tables_number   1
_cell_volume   286.659
_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  0.441  0.781  0.567  1.0
  Mg  Mg1  1  0.947  0.221  0.036  1.0
  Mg  Mg2  1  0.249  0.639  0.016  1.0
  Mg  Mg3  1  0.444  0.403  0.536  1.0
  Mg  Mg4  1  0.938  0.585  0.535  1.0
  Mg  Mg5  1  0.470  0.066  0.074  1.0
  Mg  Mg6  1  0.782  0.491  0.044  1.0
  Mg  Mg7  1  0.890  0.888  0.454  1.0
  Si  Si8  1  0.015  0.179  0.403  1.0
  Si  Si9  1  0.702  0.188  0.607  1.0
  Si  Si10  1  0.705  0.706  0.927  1.0
  Si  Si11  1  0.388  0.464  0.209  1.0
  Si  Si12  1  0.327  0.955  0.355  1.0
  Si  Si13  1  0.953  0.935  0.987  1.0
[/CIF]
.