The material structure described by Mg3Si4 crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(4), one Si(5), and two equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded to one Si(7), one Si(8), and two equivalent Si(5) atoms to form corner-sharing MgSi4 tetrahedra. In the third Mg site, Mg(3) is bonded in a trigonal non-coplanar geometry to one Si(2) and two equivalent Si(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to one Si(3), two equivalent Si(2), two equivalent Si(4), and two equivalent Si(8) atoms. In the fifth Mg site, Mg(5) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(4), two equivalent Si(5), and two equivalent Si(6) atoms. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(3), one Si(5), and two equivalent Si(8) atoms. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to two equivalent Mg(5), one Si(5), one Si(6), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 6-coordinate geometry to one Mg(3), two equivalent Mg(4), one Si(8), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 7-coordinate geometry to one Mg(4), one Mg(6), two equivalent Mg(1), two equivalent Mg(3), and one Si(7) atom. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), two equivalent Mg(4), two equivalent Mg(5), one Si(6), and one Si(8) atom. In the fifth Si site, Si(5) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(6), two equivalent Mg(2), two equivalent Mg(5), and one Si(1) atom. In the sixth Si site, Si(6) is bonded in a 6-coordinate geometry to two equivalent Mg(5), one Si(1), one Si(4), and two equivalent Si(7) atoms. In the seventh Si site, Si(7) is bonded in a 4-coordinate geometry to one Mg(2), one Si(3), and two equivalent Si(6) atoms. In the eighth Si site, Si(8) is bonded in a 7-coordinate geometry to one Mg(2), two equivalent Mg(4), two equivalent Mg(6), one Si(2), and one Si(4) atom. is represented by the CIF card [CIF]
data_Mg3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.835
_cell_length_b   8.835
_cell_length_c   8.226
_cell_angle_alpha   72.085
_cell_angle_beta   72.085
_cell_angle_gamma   27.364
_symmetry_Int_Tables_number   1
_cell_volume   279.947
_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  0.286  0.286  0.676  1.0
  Mg  Mg1  1  0.621  0.621  0.866  1.0
  Mg  Mg2  1  0.476  0.476  0.673  1.0
  Mg  Mg3  1  0.917  0.917  0.409  1.0
  Mg  Mg4  1  0.721  0.721  0.443  1.0
  Mg  Mg5  1  0.973  0.973  0.947  1.0
  Si  Si6  1  0.113  0.113  0.372  1.0
  Si  Si7  1  0.547  0.547  0.340  1.0
  Si  Si8  1  0.869  0.869  0.761  1.0
  Si  Si9  1  0.334  0.334  0.315  1.0
  Si  Si10  1  0.124  0.124  0.656  1.0
  Si  Si11  1  0.243  0.243  0.152  1.0
  Si  Si12  1  0.744  0.744  0.994  1.0
  Si  Si13  1  0.475  0.475  0.142  1.0
[/CIF]
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The material structure described by Mg3Si4 crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(4), one Si(5), and two equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded to one Si(7), one Si(8), and two equivalent Si(5) atoms to form corner-sharing MgSi4 tetrahedra. In the third Mg site, Mg(3) is bonded in a trigonal non-coplanar geometry to one Si(2) and two equivalent Si(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to one Si(3), two equivalent Si(2), two equivalent Si(4), and two equivalent Si(8) atoms. In the fifth Mg site, Mg(5) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(4), two equivalent Si(5), and two equivalent Si(6) atoms. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(3), one Si(5), and two equivalent Si(8) atoms. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to two equivalent Mg(5), one Si(5), one Si(6), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 6-coordinate geometry to one Mg(3), two equivalent Mg(4), one Si(8), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 7-coordinate geometry to one Mg(4), one Mg(6), two equivalent Mg(1), two equivalent Mg(3), and one Si(7) atom. In the fourth Si site, Si(4) is bonded in a 7-coordinate geometry to one Mg(1), two equivalent Mg(4), two equivalent Mg(5), one Si(6), and one Si(8) atom. In the fifth Si site, Si(5) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(6), two equivalent Mg(2), two equivalent Mg(5), and one Si(1) atom. In the sixth Si site, Si(6) is bonded in a 6-coordinate geometry to two equivalent Mg(5), one Si(1), one Si(4), and two equivalent Si(7) atoms. In the seventh Si site, Si(7) is bonded in a 4-coordinate geometry to one Mg(2), one Si(3), and two equivalent Si(6) atoms. In the eighth Si site, Si(8) is bonded in a 7-coordinate geometry to one Mg(2), two equivalent Mg(4), two equivalent Mg(6), one Si(2), and one Si(4) atom. is represented by the CIF card [CIF]
data_Mg3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.835
_cell_length_b   8.835
_cell_length_c   8.226
_cell_angle_alpha   72.085
_cell_angle_beta   72.085
_cell_angle_gamma   27.364
_symmetry_Int_Tables_number   1
_cell_volume   279.947
_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  0.286  0.286  0.676  1.0
  Mg  Mg1  1  0.621  0.621  0.866  1.0
  Mg  Mg2  1  0.476  0.476  0.673  1.0
  Mg  Mg3  1  0.917  0.917  0.409  1.0
  Mg  Mg4  1  0.721  0.721  0.443  1.0
  Mg  Mg5  1  0.973  0.973  0.947  1.0
  Si  Si6  1  0.113  0.113  0.372  1.0
  Si  Si7  1  0.547  0.547  0.340  1.0
  Si  Si8  1  0.869  0.869  0.761  1.0
  Si  Si9  1  0.334  0.334  0.315  1.0
  Si  Si10  1  0.124  0.124  0.656  1.0
  Si  Si11  1  0.243  0.243  0.152  1.0
  Si  Si12  1  0.744  0.744  0.994  1.0
  Si  Si13  1  0.475  0.475  0.142  1.0
[/CIF]
.