The crystal 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 Si(1), one Si(2), one Si(4), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(5), and one Si(6) atom. In the third Mg site, Mg(3) is bonded to one Si(1), one Si(3), one Si(5), and one Si(6) atom to form a mixture of distorted corner and edge-sharing MgSi4 trigonal pyramids. In the fourth Mg site, Mg(4) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), and one Si(6) atom. In the fifth Mg site, Mg(5) is bonded to one Si(1), one Si(2), one Si(3), and one Si(6) atom to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(1), one Si(2), one Si(4), and one Si(6) atom. In the seventh Mg site, Mg(7) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), one Si(4), and one Si(6) atom. In the eighth Mg site, Mg(8) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), and one Si(6) atom. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(8), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), one Mg(5), 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 7-coordinate geometry to one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(7), one Mg(8), and one Si(5) atom. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(4), one Mg(6), one Mg(7), one Mg(8), one Si(5), and one Si(6) atom. In the fifth Si site, Si(5) is bonded in a 2-coordinate geometry to one Mg(2), one Mg(3), one Si(2), one Si(3), and one Si(4) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(7), one Mg(8), and one Si(4) atom. is represented by the CIF file [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.257
_cell_length_b   7.225
_cell_length_c   7.242
_cell_angle_alpha   112.626
_cell_angle_beta   110.785
_cell_angle_gamma   91.275
_symmetry_Int_Tables_number   1
_cell_volume   277.695
_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  0.493  0.382  0.610  1.0
  Mg  Mg1  1  0.443  0.835  0.891  1.0
  Mg  Mg2  1  0.802  0.593  0.111  1.0
  Mg  Mg3  1  0.169  0.451  0.850  1.0
  Mg  Mg4  1  0.156  0.963  0.524  1.0
  Mg  Mg5  1  0.742  0.260  0.317  1.0
  Mg  Mg6  1  0.834  0.747  0.680  1.0
  Mg  Mg7  1  0.066  0.196  0.067  1.0
  Si  Si8  1  0.565  0.192  0.874  1.0
  Si  Si9  1  0.786  0.112  0.634  1.0
  Si  Si10  1  0.129  0.858  0.116  1.0
  Si  Si11  1  0.409  0.520  0.302  1.0
  Si  Si12  1  0.528  0.835  0.291  1.0
  Si  Si13  1  0.127  0.557  0.483  1.0
[/CIF]
.
The crystal 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 Si(1), one Si(2), one Si(4), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(5), and one Si(6) atom. In the third Mg site, Mg(3) is bonded to one Si(1), one Si(3), one Si(5), and one Si(6) atom to form a mixture of distorted corner and edge-sharing MgSi4 trigonal pyramids. In the fourth Mg site, Mg(4) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), and one Si(6) atom. In the fifth Mg site, Mg(5) is bonded to one Si(1), one Si(2), one Si(3), and one Si(6) atom to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(1), one Si(2), one Si(4), and one Si(6) atom. In the seventh Mg site, Mg(7) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), one Si(4), and one Si(6) atom. In the eighth Mg site, Mg(8) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), and one Si(6) atom. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(8), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), one Mg(5), 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 7-coordinate geometry to one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(7), one Mg(8), and one Si(5) atom. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(4), one Mg(6), one Mg(7), one Mg(8), one Si(5), and one Si(6) atom. In the fifth Si site, Si(5) is bonded in a 2-coordinate geometry to one Mg(2), one Mg(3), one Si(2), one Si(3), and one Si(4) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(7), one Mg(8), and one Si(4) atom. is represented by the CIF file [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.257
_cell_length_b   7.225
_cell_length_c   7.242
_cell_angle_alpha   112.626
_cell_angle_beta   110.785
_cell_angle_gamma   91.275
_symmetry_Int_Tables_number   1
_cell_volume   277.695
_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  0.493  0.382  0.610  1.0
  Mg  Mg1  1  0.443  0.835  0.891  1.0
  Mg  Mg2  1  0.802  0.593  0.111  1.0
  Mg  Mg3  1  0.169  0.451  0.850  1.0
  Mg  Mg4  1  0.156  0.963  0.524  1.0
  Mg  Mg5  1  0.742  0.260  0.317  1.0
  Mg  Mg6  1  0.834  0.747  0.680  1.0
  Mg  Mg7  1  0.066  0.196  0.067  1.0
  Si  Si8  1  0.565  0.192  0.874  1.0
  Si  Si9  1  0.786  0.112  0.634  1.0
  Si  Si10  1  0.129  0.858  0.116  1.0
  Si  Si11  1  0.409  0.520  0.302  1.0
  Si  Si12  1  0.528  0.835  0.291  1.0
  Si  Si13  1  0.127  0.557  0.483  1.0
[/CIF]
.