The structure described by Mg5Si6 crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one Si(1), one Si(2), one Si(3), and one Si(4) atom. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent Si(5), and three equivalent Si(3) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to two equivalent Si(2), three equivalent Si(4), and three equivalent Si(6) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Si(5), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent Si(2), two equivalent Si(4), and two equivalent Si(6) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), one Si(2), and one Si(5) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), one Si(1), and one Si(6) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(4), three equivalent Mg(2), one Si(3), and one Si(5) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(5), three equivalent Mg(3), and three equivalent Si(6) atoms. In the fifth Si site, Si(5) is bonded to one Mg(4), two equivalent Mg(2), one Si(1), one Si(3), and two equivalent Si(5) atoms to form a mixture of distorted corner and edge-sharing SiMg3Si4 hexagonal pyramids. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to two equivalent Mg(5), three equivalent Mg(3), one Si(2), and three equivalent Si(4) atoms. is represented by the CIF card [CIF]
data_Mg5Si6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.120
_cell_length_b   6.893
_cell_length_c   14.473
_cell_angle_alpha   82.056
_cell_angle_beta   85.143
_cell_angle_gamma   88.207
_symmetry_Int_Tables_number   1
_cell_volume   405.522
_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  0.857  0.888  0.756  1.0
  Mg  Mg1  1  0.143  0.112  0.244  1.0
  Mg  Mg2  1  0.555  0.202  0.404  1.0
  Mg  Mg3  1  0.706  0.968  0.093  1.0
  Mg  Mg4  1  0.294  0.032  0.907  1.0
  Mg  Mg5  1  0.445  0.798  0.596  1.0
  Mg  Mg6  1  0.638  0.780  0.322  1.0
  Mg  Mg7  1  0.662  0.443  0.177  1.0
  Mg  Mg8  1  0.338  0.557  0.823  1.0
  Mg  Mg9  1  0.362  0.220  0.678  1.0
  Si  Si10  1  0.895  0.537  0.687  1.0
  Si  Si11  1  0.817  0.253  0.805  1.0
  Si  Si12  1  0.183  0.747  0.195  1.0
  Si  Si13  1  0.105  0.463  0.313  1.0
  Si  Si14  1  0.932  0.079  0.568  1.0
  Si  Si15  1  0.766  0.716  0.943  1.0
  Si  Si16  1  0.234  0.284  0.057  1.0
  Si  Si17  1  0.239  0.568  0.461  1.0
  Si  Si18  1  0.761  0.432  0.539  1.0
  Si  Si19  1  0.761  0.345  0.959  1.0
  Si  Si20  1  0.239  0.655  0.041  1.0
  Si  Si21  1  0.068  0.921  0.432  1.0
[/CIF]
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The structure described by Mg5Si6 crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one Si(1), one Si(2), one Si(3), and one Si(4) atom. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent Si(5), and three equivalent Si(3) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to two equivalent Si(2), three equivalent Si(4), and three equivalent Si(6) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Si(5), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent Si(2), two equivalent Si(4), and two equivalent Si(6) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), one Si(2), and one Si(5) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), one Si(1), and one Si(6) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(4), three equivalent Mg(2), one Si(3), and one Si(5) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(5), three equivalent Mg(3), and three equivalent Si(6) atoms. In the fifth Si site, Si(5) is bonded to one Mg(4), two equivalent Mg(2), one Si(1), one Si(3), and two equivalent Si(5) atoms to form a mixture of distorted corner and edge-sharing SiMg3Si4 hexagonal pyramids. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to two equivalent Mg(5), three equivalent Mg(3), one Si(2), and three equivalent Si(4) atoms. is represented by the CIF card [CIF]
data_Mg5Si6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.120
_cell_length_b   6.893
_cell_length_c   14.473
_cell_angle_alpha   82.056
_cell_angle_beta   85.143
_cell_angle_gamma   88.207
_symmetry_Int_Tables_number   1
_cell_volume   405.522
_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  0.857  0.888  0.756  1.0
  Mg  Mg1  1  0.143  0.112  0.244  1.0
  Mg  Mg2  1  0.555  0.202  0.404  1.0
  Mg  Mg3  1  0.706  0.968  0.093  1.0
  Mg  Mg4  1  0.294  0.032  0.907  1.0
  Mg  Mg5  1  0.445  0.798  0.596  1.0
  Mg  Mg6  1  0.638  0.780  0.322  1.0
  Mg  Mg7  1  0.662  0.443  0.177  1.0
  Mg  Mg8  1  0.338  0.557  0.823  1.0
  Mg  Mg9  1  0.362  0.220  0.678  1.0
  Si  Si10  1  0.895  0.537  0.687  1.0
  Si  Si11  1  0.817  0.253  0.805  1.0
  Si  Si12  1  0.183  0.747  0.195  1.0
  Si  Si13  1  0.105  0.463  0.313  1.0
  Si  Si14  1  0.932  0.079  0.568  1.0
  Si  Si15  1  0.766  0.716  0.943  1.0
  Si  Si16  1  0.234  0.284  0.057  1.0
  Si  Si17  1  0.239  0.568  0.461  1.0
  Si  Si18  1  0.761  0.432  0.539  1.0
  Si  Si19  1  0.761  0.345  0.959  1.0
  Si  Si20  1  0.239  0.655  0.041  1.0
  Si  Si21  1  0.068  0.921  0.432  1.0
[/CIF]
.