The material structure described by Mg4Si7 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 8-coordinate geometry to two equivalent Si(2), two equivalent Si(4), and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a square co-planar geometry to two equivalent Si(3) and two equivalent Si(5) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(4), one Si(6), two equivalent Si(3), two equivalent Si(5), and two equivalent Si(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to one Si(1), one Si(5), one Si(6), one Si(7), two equivalent Si(2), and two equivalent Si(4) atoms. In the fifth Mg site, Mg(5) is bonded in a 8-coordinate geometry to two equivalent Si(5), two equivalent Si(7), and four equivalent Si(3) atoms. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to one Mg(4), two equivalent Mg(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(1), two equivalent Mg(4), one Si(2), one Si(6), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), four equivalent Mg(5), one Si(3), and one Si(7) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(4), one Si(6), two equivalent Si(1), and two equivalent Si(7) atoms. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(2), one Mg(4), two equivalent Mg(3), two equivalent Mg(5), one Si(7), and two equivalent Si(6) atoms. In the sixth Si site, Si(6) is bonded in a 6-coordinate geometry to one Mg(3), one Mg(4), one Si(2), one Si(4), and two equivalent Si(5) atoms. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(4), two equivalent Mg(3), two equivalent Mg(5), one Si(3), one Si(5), and two equivalent Si(4) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.915
_cell_length_b   7.168
_cell_length_c   14.171
_cell_angle_alpha   80.849
_cell_angle_beta   89.374
_cell_angle_gamma   87.123
_symmetry_Int_Tables_number   1
_cell_volume   392.168
_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  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.500  0.500  0.500  1.0
  Mg  Mg2  1  0.996  0.263  0.660  1.0
  Mg  Mg3  1  0.004  0.737  0.340  1.0
  Mg  Mg4  1  0.531  0.799  0.154  1.0
  Mg  Mg5  1  0.469  0.201  0.846  1.0
  Mg  Mg6  1  0.006  0.787  0.579  1.0
  Mg  Mg7  1  0.994  0.213  0.421  1.0
  Si  Si8  1  0.443  0.253  0.050  1.0
  Si  Si9  1  0.557  0.747  0.950  1.0
  Si  Si10  1  0.916  0.386  0.953  1.0
  Si  Si11  1  0.084  0.614  0.047  1.0
  Si  Si12  1  0.499  0.891  0.443  1.0
  Si  Si13  1  0.501  0.109  0.557  1.0
  Si  Si14  1  0.013  0.903  0.815  1.0
  Si  Si15  1  0.987  0.097  0.185  1.0
  Si  Si16  1  0.494  0.451  0.305  1.0
  Si  Si17  1  0.506  0.549  0.695  1.0
  Si  Si18  1  0.994  0.563  0.797  1.0
  Si  Si19  1  0.006  0.437  0.203  1.0
  Si  Si20  1  0.485  0.088  0.291  1.0
  Si  Si21  1  0.515  0.912  0.709  1.0
[/CIF]
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The material structure described by Mg4Si7 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 8-coordinate geometry to two equivalent Si(2), two equivalent Si(4), and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a square co-planar geometry to two equivalent Si(3) and two equivalent Si(5) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Si(4), one Si(6), two equivalent Si(3), two equivalent Si(5), and two equivalent Si(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to one Si(1), one Si(5), one Si(6), one Si(7), two equivalent Si(2), and two equivalent Si(4) atoms. In the fifth Mg site, Mg(5) is bonded in a 8-coordinate geometry to two equivalent Si(5), two equivalent Si(7), and four equivalent Si(3) atoms. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to one Mg(4), two equivalent Mg(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(1), two equivalent Mg(4), one Si(2), one Si(6), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), four equivalent Mg(5), one Si(3), and one Si(7) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(4), one Si(6), two equivalent Si(1), and two equivalent Si(7) atoms. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(2), one Mg(4), two equivalent Mg(3), two equivalent Mg(5), one Si(7), and two equivalent Si(6) atoms. In the sixth Si site, Si(6) is bonded in a 6-coordinate geometry to one Mg(3), one Mg(4), one Si(2), one Si(4), and two equivalent Si(5) atoms. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(4), two equivalent Mg(3), two equivalent Mg(5), one Si(3), one Si(5), and two equivalent Si(4) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.915
_cell_length_b   7.168
_cell_length_c   14.171
_cell_angle_alpha   80.849
_cell_angle_beta   89.374
_cell_angle_gamma   87.123
_symmetry_Int_Tables_number   1
_cell_volume   392.168
_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  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.500  0.500  0.500  1.0
  Mg  Mg2  1  0.996  0.263  0.660  1.0
  Mg  Mg3  1  0.004  0.737  0.340  1.0
  Mg  Mg4  1  0.531  0.799  0.154  1.0
  Mg  Mg5  1  0.469  0.201  0.846  1.0
  Mg  Mg6  1  0.006  0.787  0.579  1.0
  Mg  Mg7  1  0.994  0.213  0.421  1.0
  Si  Si8  1  0.443  0.253  0.050  1.0
  Si  Si9  1  0.557  0.747  0.950  1.0
  Si  Si10  1  0.916  0.386  0.953  1.0
  Si  Si11  1  0.084  0.614  0.047  1.0
  Si  Si12  1  0.499  0.891  0.443  1.0
  Si  Si13  1  0.501  0.109  0.557  1.0
  Si  Si14  1  0.013  0.903  0.815  1.0
  Si  Si15  1  0.987  0.097  0.185  1.0
  Si  Si16  1  0.494  0.451  0.305  1.0
  Si  Si17  1  0.506  0.549  0.695  1.0
  Si  Si18  1  0.994  0.563  0.797  1.0
  Si  Si19  1  0.006  0.437  0.203  1.0
  Si  Si20  1  0.485  0.088  0.291  1.0
  Si  Si21  1  0.515  0.912  0.709  1.0
[/CIF]
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