The material described by Mg4Si3 crystallizes in the triclinic P1 space group. There are sixteen inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Si(12), one Si(4), one Si(5), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a distorted tetrahedral geometry to one Si(12), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(10), one Si(2), one Si(7), and one Si(8) atom. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(11), one Si(12), one Si(4), one Si(7), and one Si(8) atom. In the fifth Mg site, Mg(5) is bonded in a 4-coordinate geometry to one Si(11), one Si(3), one Si(5), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(12), one Si(4), one Si(5), and one Si(6) atom. In the seventh Mg site, Mg(7) is bonded in a 3-coordinate geometry to one Si(1), one Si(2), one Si(7), and one Si(9) atom. In the eighth Mg site, Mg(8) is bonded in a 6-coordinate geometry to one Si(1), one Si(10), one Si(2), one Si(7), one Si(8), and one Si(9) atom. In the ninth Mg site, Mg(9) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(5), one Si(6), and one Si(9) atom. In the tenth Mg site, Mg(10) is bonded in a 5-coordinate geometry to one Si(1), one Si(10), one Si(5), one Si(6), and one Si(9) atom. In the eleventh Mg site, Mg(11) is bonded in a 5-coordinate geometry to one Si(11), one Si(12), one Si(3), one Si(4), and one Si(8) atom. In the twelfth Mg site, Mg(12) is bonded in a 3-coordinate geometry to one Si(10), one Si(12), one Si(7), and one Si(8) atom. In the thirteenth Mg site, Mg(13) is bonded in a 6-coordinate geometry to one Si(1), one Si(10), one Si(2), one Si(5), one Si(6), and one Si(9) atom. In the fourteenth Mg site, Mg(14) is bonded in a 4-coordinate geometry to one Si(1), one Si(10), one Si(6), and one Si(9) atom. In the fifteenth Mg site, Mg(15) is bonded in a 4-coordinate geometry to one Si(12), one Si(4), one Si(7), and one Si(8) atom. In the sixteenth Mg site, Mg(16) is bonded in a 4-coordinate geometry to one Si(11), one Si(12), one Si(3), and one Si(8) atom. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(13), one Mg(14), one Mg(7), one Mg(8), one Mg(9), one Si(10), one Si(6), and one Si(9) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(13), one Mg(3), one Mg(7), one Mg(8), one Mg(9), one Si(10), and one Si(7) atom. In the third Si site, Si(3) is bonded in a 7-coordinate geometry to one Mg(11), one Mg(16), one Mg(2), one Mg(5), one Si(11), one Si(12), and one Si(8) atom. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(11), one Mg(15), one Mg(2), one Mg(4), one Mg(6), one Si(11), and one Si(12) atom. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(10), one Mg(13), one Mg(2), one Mg(5), one Mg(6), one Mg(9), and one Si(11) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(10), one Mg(13), one Mg(14), one Mg(2), one Mg(5), one Mg(6), one Mg(9), and one Si(1) atom. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Mg(12), one Mg(15), one Mg(3), one Mg(4), one Mg(7), one Mg(8), one Si(2), and one Si(9) atom. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Mg(11), one Mg(12), one Mg(15), one Mg(16), one Mg(3), one Mg(4), one Mg(8), and one Si(3) atom. In the ninth Si site, Si(9) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(13), one Mg(14), one Mg(7), one Mg(8), one Mg(9), one Si(1), and one Si(7) atom. In the tenth Si site, Si(10) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(12), one Mg(13), one Mg(14), one Mg(3), one Mg(8), one Si(1), and one Si(2) atom. In the eleventh Si site, Si(11) is bonded in a 7-coordinate geometry to one Mg(11), one Mg(16), one Mg(4), one Mg(5), one Si(3), one Si(4), and one Si(5) atom. In the twelfth Si site, Si(12) is bonded in a 10-coordinate geometry to one Mg(1), one Mg(11), one Mg(12), one Mg(15), one Mg(16), one Mg(2), one Mg(4), one Mg(6), one Si(3), and one Si(4) atom. is represented by the CIF card [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.596
_cell_length_b   7.161
_cell_length_c   12.480
_cell_angle_alpha   97.795
_cell_angle_beta   87.837
_cell_angle_gamma   106.344
_symmetry_Int_Tables_number   1
_cell_volume   560.474
_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  0.696  0.861  0.889  1.0
  Mg  Mg1  1  0.522  0.397  0.907  1.0
  Mg  Mg2  1  0.089  0.920  0.362  1.0
  Mg  Mg3  1  0.113  0.547  0.198  1.0
  Mg  Mg4  1  0.208  0.953  0.838  1.0
  Mg  Mg5  1  0.003  0.282  0.898  1.0
  Mg  Mg6  1  0.556  0.812  0.411  1.0
  Mg  Mg7  1  0.433  0.305  0.413  1.0
  Mg  Mg8  1  0.405  0.792  0.641  1.0
  Mg  Mg9  1  0.338  0.290  0.673  1.0
  Mg  Mg10  1  0.927  0.937  0.117  1.0
  Mg  Mg11  1  0.843  0.204  0.311  1.0
  Mg  Mg12  1  0.949  0.495  0.698  1.0
  Mg  Mg13  1  0.915  0.929  0.649  1.0
  Mg  Mg14  1  0.608  0.525  0.200  1.0
  Mg  Mg15  1  0.464  0.927  0.195  1.0
  Si  Si16  1  0.668  0.160  0.558  1.0
  Si  Si17  1  0.156  0.567  0.474  1.0
  Si  Si18  1  0.352  0.126  0.039  1.0
  Si  Si19  1  0.858  0.575  0.025  1.0
  Si  Si20  1  0.303  0.604  0.828  1.0
  Si  Si21  1  0.637  0.140  0.756  1.0
  Si  Si22  1  0.829  0.572  0.395  1.0
  Si  Si23  1  0.240  0.223  0.219  1.0
  Si  Si24  1  0.664  0.558  0.573  1.0
  Si  Si25  1  0.037  0.221  0.514  1.0
  Si  Si26  1  0.235  0.733  0.011  1.0
  Si  Si27  1  0.734  0.203  0.071  1.0
[/CIF]
.
The material described by Mg4Si3 crystallizes in the triclinic P1 space group. There are sixteen inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Si(12), one Si(4), one Si(5), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a distorted tetrahedral geometry to one Si(12), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to one Si(10), one Si(2), one Si(7), and one Si(8) atom. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(11), one Si(12), one Si(4), one Si(7), and one Si(8) atom. In the fifth Mg site, Mg(5) is bonded in a 4-coordinate geometry to one Si(11), one Si(3), one Si(5), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(12), one Si(4), one Si(5), and one Si(6) atom. In the seventh Mg site, Mg(7) is bonded in a 3-coordinate geometry to one Si(1), one Si(2), one Si(7), and one Si(9) atom. In the eighth Mg site, Mg(8) is bonded in a 6-coordinate geometry to one Si(1), one Si(10), one Si(2), one Si(7), one Si(8), and one Si(9) atom. In the ninth Mg site, Mg(9) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(5), one Si(6), and one Si(9) atom. In the tenth Mg site, Mg(10) is bonded in a 5-coordinate geometry to one Si(1), one Si(10), one Si(5), one Si(6), and one Si(9) atom. In the eleventh Mg site, Mg(11) is bonded in a 5-coordinate geometry to one Si(11), one Si(12), one Si(3), one Si(4), and one Si(8) atom. In the twelfth Mg site, Mg(12) is bonded in a 3-coordinate geometry to one Si(10), one Si(12), one Si(7), and one Si(8) atom. In the thirteenth Mg site, Mg(13) is bonded in a 6-coordinate geometry to one Si(1), one Si(10), one Si(2), one Si(5), one Si(6), and one Si(9) atom. In the fourteenth Mg site, Mg(14) is bonded in a 4-coordinate geometry to one Si(1), one Si(10), one Si(6), and one Si(9) atom. In the fifteenth Mg site, Mg(15) is bonded in a 4-coordinate geometry to one Si(12), one Si(4), one Si(7), and one Si(8) atom. In the sixteenth Mg site, Mg(16) is bonded in a 4-coordinate geometry to one Si(11), one Si(12), one Si(3), and one Si(8) atom. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(13), one Mg(14), one Mg(7), one Mg(8), one Mg(9), one Si(10), one Si(6), and one Si(9) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(13), one Mg(3), one Mg(7), one Mg(8), one Mg(9), one Si(10), and one Si(7) atom. In the third Si site, Si(3) is bonded in a 7-coordinate geometry to one Mg(11), one Mg(16), one Mg(2), one Mg(5), one Si(11), one Si(12), and one Si(8) atom. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(11), one Mg(15), one Mg(2), one Mg(4), one Mg(6), one Si(11), and one Si(12) atom. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(10), one Mg(13), one Mg(2), one Mg(5), one Mg(6), one Mg(9), and one Si(11) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(10), one Mg(13), one Mg(14), one Mg(2), one Mg(5), one Mg(6), one Mg(9), and one Si(1) atom. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Mg(12), one Mg(15), one Mg(3), one Mg(4), one Mg(7), one Mg(8), one Si(2), and one Si(9) atom. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Mg(11), one Mg(12), one Mg(15), one Mg(16), one Mg(3), one Mg(4), one Mg(8), and one Si(3) atom. In the ninth Si site, Si(9) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(13), one Mg(14), one Mg(7), one Mg(8), one Mg(9), one Si(1), and one Si(7) atom. In the tenth Si site, Si(10) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(12), one Mg(13), one Mg(14), one Mg(3), one Mg(8), one Si(1), and one Si(2) atom. In the eleventh Si site, Si(11) is bonded in a 7-coordinate geometry to one Mg(11), one Mg(16), one Mg(4), one Mg(5), one Si(3), one Si(4), and one Si(5) atom. In the twelfth Si site, Si(12) is bonded in a 10-coordinate geometry to one Mg(1), one Mg(11), one Mg(12), one Mg(15), one Mg(16), one Mg(2), one Mg(4), one Mg(6), one Si(3), and one Si(4) atom. is represented by the CIF card [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.596
_cell_length_b   7.161
_cell_length_c   12.480
_cell_angle_alpha   97.795
_cell_angle_beta   87.837
_cell_angle_gamma   106.344
_symmetry_Int_Tables_number   1
_cell_volume   560.474
_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  0.696  0.861  0.889  1.0
  Mg  Mg1  1  0.522  0.397  0.907  1.0
  Mg  Mg2  1  0.089  0.920  0.362  1.0
  Mg  Mg3  1  0.113  0.547  0.198  1.0
  Mg  Mg4  1  0.208  0.953  0.838  1.0
  Mg  Mg5  1  0.003  0.282  0.898  1.0
  Mg  Mg6  1  0.556  0.812  0.411  1.0
  Mg  Mg7  1  0.433  0.305  0.413  1.0
  Mg  Mg8  1  0.405  0.792  0.641  1.0
  Mg  Mg9  1  0.338  0.290  0.673  1.0
  Mg  Mg10  1  0.927  0.937  0.117  1.0
  Mg  Mg11  1  0.843  0.204  0.311  1.0
  Mg  Mg12  1  0.949  0.495  0.698  1.0
  Mg  Mg13  1  0.915  0.929  0.649  1.0
  Mg  Mg14  1  0.608  0.525  0.200  1.0
  Mg  Mg15  1  0.464  0.927  0.195  1.0
  Si  Si16  1  0.668  0.160  0.558  1.0
  Si  Si17  1  0.156  0.567  0.474  1.0
  Si  Si18  1  0.352  0.126  0.039  1.0
  Si  Si19  1  0.858  0.575  0.025  1.0
  Si  Si20  1  0.303  0.604  0.828  1.0
  Si  Si21  1  0.637  0.140  0.756  1.0
  Si  Si22  1  0.829  0.572  0.395  1.0
  Si  Si23  1  0.240  0.223  0.219  1.0
  Si  Si24  1  0.664  0.558  0.573  1.0
  Si  Si25  1  0.037  0.221  0.514  1.0
  Si  Si26  1  0.235  0.733  0.011  1.0
  Si  Si27  1  0.734  0.203  0.071  1.0
[/CIF]
.