The compound described by Mg3Si4 is Magnesium tetraboride-like structured and crystallizes in the triclinic P1 space group. There are twelve inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to one Si(13), one Si(15), one Si(3), one Si(4), one Si(7), one Si(8), and one Si(9) atom. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(10), one Si(11), one Si(13), one Si(15), one Si(3), one Si(4), one Si(7), and one Si(8) atom. In the third Mg site, Mg(3) is bonded to one Si(1), one Si(12), one Si(14), one Si(16), one Si(6), and one Si(9) atom to form distorted corner-sharing MgSi6 trigonal bipyramids. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Si(1), one Si(11), one Si(12), one Si(15), one Si(16), and one Si(6) atom. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to one Si(1), one Si(10), one Si(12), one Si(13), one Si(14), one Si(5), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 5-coordinate geometry to one Si(1), one Si(13), one Si(14), one Si(6), and one Si(9) atom. In the seventh Mg site, Mg(7) is bonded in a 7-coordinate geometry to one Si(15), one Si(16), one Si(2), one Si(3), one Si(4), one Si(7), and one Si(8) atom. In the eighth Mg site, Mg(8) is bonded in a 6-coordinate geometry to one Si(11), one Si(13), one Si(15), one Si(3), one Si(4), and one Si(7) atom. In the ninth Mg site, Mg(9) is bonded to one Si(14), one Si(3), one Si(4), one Si(7), and one Si(9) atom to form distorted corner-sharing MgSi5 square pyramids. In the tenth Mg site, Mg(10) is bonded in a 6-coordinate geometry to one Si(12), one Si(13), one Si(14), one Si(3), one Si(4), one Si(5), and one Si(9) atom. In the eleventh Mg site, Mg(11) is bonded in a 6-coordinate geometry to one Si(1), one Si(11), one Si(15), one Si(2), one Si(6), one Si(7), and one Si(8) atom. In the twelfth Mg site, Mg(12) is bonded in a 8-coordinate geometry to one Si(1), one Si(11), one Si(12), one Si(15), one Si(16), one Si(2), one Si(6), and one Si(8) atom. There are sixteen inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(11), one Mg(12), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Si(11), and one Si(14) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(11), one Mg(12), one Mg(7), one Si(11), one Si(12), one Si(16), and one Si(7) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(10), one Mg(2), one Mg(7), one Mg(8), one Mg(9), one Si(10), one Si(15), and one Si(9) atom. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(10), one Mg(2), one Mg(7), one Mg(8), one Mg(9), one Si(13), and one Si(5) atom. In the fifth Si site, Si(5) is bonded in a 6-coordinate geometry to one Mg(10), one Mg(5), one Si(10), one Si(14), one Si(4), and one Si(6) atom. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(11), one Mg(12), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Si(12), and one Si(5) atom. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(11), one Mg(2), one Mg(7), one Mg(8), one Mg(9), one Si(15), and one Si(2) atom. In the eighth Si site, Si(8) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(11), one Mg(12), one Mg(2), one Mg(7), one Si(11), and one Si(16) atom. In the ninth Si site, Si(9) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(10), one Mg(3), one Mg(6), one Mg(9), one Si(10), and one Si(3) atom. In the tenth Si site, Si(10) is bonded in a 6-coordinate geometry to one Mg(2), one Mg(5), one Si(13), one Si(3), one Si(5), and one Si(9) atom. In the eleventh Si site, Si(11) is bonded in a 9-coordinate geometry to one Mg(11), one Mg(12), one Mg(2), one Mg(4), one Mg(8), one Si(1), one Si(16), one Si(2), and one Si(8) atom. In the twelfth Si site, Si(12) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(12), one Mg(3), one Mg(4), one Mg(5), one Si(16), one Si(2), and one Si(6) atom. In the thirteenth Si site, Si(13) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(10), one Mg(2), one Mg(5), one Mg(6), one Mg(8), one Si(10), and one Si(4) atom. In the fourteenth Si site, Si(14) is bonded in a 7-coordinate geometry to one Mg(10), one Mg(3), one Mg(5), one Mg(6), one Mg(9), one Si(1), and one Si(5) atom. In the fifteenth Si site, Si(15) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(11), one Mg(12), one Mg(2), one Mg(4), one Mg(7), one Mg(8), one Si(3), and one Si(7) atom. In the sixteenth Si site, Si(16) is bonded in a 8-coordinate geometry to one Mg(12), one Mg(3), one Mg(4), one Mg(7), one Si(11), one Si(12), one Si(2), and one Si(8) atom. is represented by the CIF file [CIF]
data_Mg3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.726
_cell_length_b   7.264
_cell_length_c   11.763
_cell_angle_alpha   107.208
_cell_angle_beta   87.679
_cell_angle_gamma   104.759
_symmetry_Int_Tables_number   1
_cell_volume   530.525
_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  0.352  0.914  0.547  1.0
  Mg  Mg1  1  0.555  0.574  0.620  1.0
  Mg  Mg2  1  0.280  0.073  0.122  1.0
  Mg  Mg3  1  0.044  0.215  0.926  1.0
  Mg  Mg4  1  0.695  0.425  0.200  1.0
  Mg  Mg5  1  0.566  0.823  0.217  1.0
  Mg  Mg6  1  0.064  0.556  0.667  1.0
  Mg  Mg7  1  0.886  0.996  0.642  1.0
  Mg  Mg8  1  0.802  0.231  0.445  1.0
  Mg  Mg9  1  0.028  0.846  0.292  1.0
  Mg  Mg10  1  0.534  0.249  0.921  1.0
  Mg  Mg11  1  0.400  0.638  0.923  1.0
  Si  Si12  1  0.667  0.042  0.048  1.0
  Si  Si13  1  0.797  0.567  0.864  1.0
  Si  Si14  1  0.186  0.227  0.514  1.0
  Si  Si15  1  0.956  0.639  0.467  1.0
  Si  Si16  1  0.097  0.459  0.275  1.0
  Si  Si17  1  0.318  0.469  0.101  1.0
  Si  Si18  1  0.672  0.292  0.691  1.0
  Si  Si19  1  0.386  0.869  0.769  1.0
  Si  Si20  1  0.412  0.111  0.360  1.0
  Si  Si21  1  0.369  0.434  0.387  1.0
  Si  Si22  1  0.735  0.874  0.841  1.0
  Si  Si23  1  0.014  0.612  0.045  1.0
  Si  Si24  1  0.652  0.731  0.423  1.0
  Si  Si25  1  0.911  0.114  0.203  1.0
  Si  Si26  1  0.294  0.273  0.718  1.0
  Si  Si27  1  0.109  0.839  0.903  1.0
[/CIF]
.
The compound described by Mg3Si4 is Magnesium tetraboride-like structured and crystallizes in the triclinic P1 space group. There are twelve inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to one Si(13), one Si(15), one Si(3), one Si(4), one Si(7), one Si(8), and one Si(9) atom. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(10), one Si(11), one Si(13), one Si(15), one Si(3), one Si(4), one Si(7), and one Si(8) atom. In the third Mg site, Mg(3) is bonded to one Si(1), one Si(12), one Si(14), one Si(16), one Si(6), and one Si(9) atom to form distorted corner-sharing MgSi6 trigonal bipyramids. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Si(1), one Si(11), one Si(12), one Si(15), one Si(16), and one Si(6) atom. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to one Si(1), one Si(10), one Si(12), one Si(13), one Si(14), one Si(5), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 5-coordinate geometry to one Si(1), one Si(13), one Si(14), one Si(6), and one Si(9) atom. In the seventh Mg site, Mg(7) is bonded in a 7-coordinate geometry to one Si(15), one Si(16), one Si(2), one Si(3), one Si(4), one Si(7), and one Si(8) atom. In the eighth Mg site, Mg(8) is bonded in a 6-coordinate geometry to one Si(11), one Si(13), one Si(15), one Si(3), one Si(4), and one Si(7) atom. In the ninth Mg site, Mg(9) is bonded to one Si(14), one Si(3), one Si(4), one Si(7), and one Si(9) atom to form distorted corner-sharing MgSi5 square pyramids. In the tenth Mg site, Mg(10) is bonded in a 6-coordinate geometry to one Si(12), one Si(13), one Si(14), one Si(3), one Si(4), one Si(5), and one Si(9) atom. In the eleventh Mg site, Mg(11) is bonded in a 6-coordinate geometry to one Si(1), one Si(11), one Si(15), one Si(2), one Si(6), one Si(7), and one Si(8) atom. In the twelfth Mg site, Mg(12) is bonded in a 8-coordinate geometry to one Si(1), one Si(11), one Si(12), one Si(15), one Si(16), one Si(2), one Si(6), and one Si(8) atom. There are sixteen inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(11), one Mg(12), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Si(11), and one Si(14) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(11), one Mg(12), one Mg(7), one Si(11), one Si(12), one Si(16), and one Si(7) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(10), one Mg(2), one Mg(7), one Mg(8), one Mg(9), one Si(10), one Si(15), and one Si(9) atom. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(10), one Mg(2), one Mg(7), one Mg(8), one Mg(9), one Si(13), and one Si(5) atom. In the fifth Si site, Si(5) is bonded in a 6-coordinate geometry to one Mg(10), one Mg(5), one Si(10), one Si(14), one Si(4), and one Si(6) atom. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(11), one Mg(12), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Si(12), and one Si(5) atom. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(11), one Mg(2), one Mg(7), one Mg(8), one Mg(9), one Si(15), and one Si(2) atom. In the eighth Si site, Si(8) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(11), one Mg(12), one Mg(2), one Mg(7), one Si(11), and one Si(16) atom. In the ninth Si site, Si(9) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(10), one Mg(3), one Mg(6), one Mg(9), one Si(10), and one Si(3) atom. In the tenth Si site, Si(10) is bonded in a 6-coordinate geometry to one Mg(2), one Mg(5), one Si(13), one Si(3), one Si(5), and one Si(9) atom. In the eleventh Si site, Si(11) is bonded in a 9-coordinate geometry to one Mg(11), one Mg(12), one Mg(2), one Mg(4), one Mg(8), one Si(1), one Si(16), one Si(2), and one Si(8) atom. In the twelfth Si site, Si(12) is bonded in a 8-coordinate geometry to one Mg(10), one Mg(12), one Mg(3), one Mg(4), one Mg(5), one Si(16), one Si(2), and one Si(6) atom. In the thirteenth Si site, Si(13) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(10), one Mg(2), one Mg(5), one Mg(6), one Mg(8), one Si(10), and one Si(4) atom. In the fourteenth Si site, Si(14) is bonded in a 7-coordinate geometry to one Mg(10), one Mg(3), one Mg(5), one Mg(6), one Mg(9), one Si(1), and one Si(5) atom. In the fifteenth Si site, Si(15) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(11), one Mg(12), one Mg(2), one Mg(4), one Mg(7), one Mg(8), one Si(3), and one Si(7) atom. In the sixteenth Si site, Si(16) is bonded in a 8-coordinate geometry to one Mg(12), one Mg(3), one Mg(4), one Mg(7), one Si(11), one Si(12), one Si(2), and one Si(8) atom. is represented by the CIF file [CIF]
data_Mg3Si4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.726
_cell_length_b   7.264
_cell_length_c   11.763
_cell_angle_alpha   107.208
_cell_angle_beta   87.679
_cell_angle_gamma   104.759
_symmetry_Int_Tables_number   1
_cell_volume   530.525
_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  0.352  0.914  0.547  1.0
  Mg  Mg1  1  0.555  0.574  0.620  1.0
  Mg  Mg2  1  0.280  0.073  0.122  1.0
  Mg  Mg3  1  0.044  0.215  0.926  1.0
  Mg  Mg4  1  0.695  0.425  0.200  1.0
  Mg  Mg5  1  0.566  0.823  0.217  1.0
  Mg  Mg6  1  0.064  0.556  0.667  1.0
  Mg  Mg7  1  0.886  0.996  0.642  1.0
  Mg  Mg8  1  0.802  0.231  0.445  1.0
  Mg  Mg9  1  0.028  0.846  0.292  1.0
  Mg  Mg10  1  0.534  0.249  0.921  1.0
  Mg  Mg11  1  0.400  0.638  0.923  1.0
  Si  Si12  1  0.667  0.042  0.048  1.0
  Si  Si13  1  0.797  0.567  0.864  1.0
  Si  Si14  1  0.186  0.227  0.514  1.0
  Si  Si15  1  0.956  0.639  0.467  1.0
  Si  Si16  1  0.097  0.459  0.275  1.0
  Si  Si17  1  0.318  0.469  0.101  1.0
  Si  Si18  1  0.672  0.292  0.691  1.0
  Si  Si19  1  0.386  0.869  0.769  1.0
  Si  Si20  1  0.412  0.111  0.360  1.0
  Si  Si21  1  0.369  0.434  0.387  1.0
  Si  Si22  1  0.735  0.874  0.841  1.0
  Si  Si23  1  0.014  0.612  0.045  1.0
  Si  Si24  1  0.652  0.731  0.423  1.0
  Si  Si25  1  0.911  0.114  0.203  1.0
  Si  Si26  1  0.294  0.273  0.718  1.0
  Si  Si27  1  0.109  0.839  0.903  1.0
[/CIF]
.