The crystal structure described by Mg4Si7 crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(2), one Si(4), two equivalent Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one Mg(1), one Si(4), two equivalent Si(1), two equivalent Si(2), and three equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), one Si(2), and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Mg(1), three equivalent Mg(2), and three equivalent Si(1) atoms. In the fourth Si site, Si(4) is bonded in a distorted body-centered cubic geometry to two equivalent Mg(1), two equivalent Mg(2), and four equivalent Si(2) atoms. is represented by the CIF file [CIF]
data_Mg4Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.244
_cell_length_b   8.244
_cell_length_c   6.768
_cell_angle_alpha   89.628
_cell_angle_beta   89.628
_cell_angle_gamma   25.595
_symmetry_Int_Tables_number   1
_cell_volume   198.710
_cell_formula_units_Z   1
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  0.921  0.921  0.399  1.0
  Mg  Mg1  1  0.079  0.079  0.601  1.0
  Mg  Mg2  1  0.165  0.165  0.007  1.0
  Mg  Mg3  1  0.835  0.835  0.993  1.0
  Si  Si4  1  0.690  0.690  0.342  1.0
  Si  Si5  1  0.310  0.310  0.658  1.0
  Si  Si6  1  0.545  0.545  0.242  1.0
  Si  Si7  1  0.455  0.455  0.758  1.0
  Si  Si8  1  0.288  0.288  0.290  1.0
  Si  Si9  1  0.712  0.712  0.710  1.0
  Si  Si10  1  0.000  0.000  0.000  1.0
[/CIF]
.
The crystal structure described by Mg4Si7 crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(2), one Si(4), two equivalent Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one Mg(1), one Si(4), two equivalent Si(1), two equivalent Si(2), and three equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), one Si(2), and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Mg(1), three equivalent Mg(2), and three equivalent Si(1) atoms. In the fourth Si site, Si(4) is bonded in a distorted body-centered cubic geometry to two equivalent Mg(1), two equivalent Mg(2), and four equivalent Si(2) atoms. is represented by the CIF file [CIF]
data_Mg4Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.244
_cell_length_b   8.244
_cell_length_c   6.768
_cell_angle_alpha   89.628
_cell_angle_beta   89.628
_cell_angle_gamma   25.595
_symmetry_Int_Tables_number   1
_cell_volume   198.710
_cell_formula_units_Z   1
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  0.921  0.921  0.399  1.0
  Mg  Mg1  1  0.079  0.079  0.601  1.0
  Mg  Mg2  1  0.165  0.165  0.007  1.0
  Mg  Mg3  1  0.835  0.835  0.993  1.0
  Si  Si4  1  0.690  0.690  0.342  1.0
  Si  Si5  1  0.310  0.310  0.658  1.0
  Si  Si6  1  0.545  0.545  0.242  1.0
  Si  Si7  1  0.455  0.455  0.758  1.0
  Si  Si8  1  0.288  0.288  0.290  1.0
  Si  Si9  1  0.712  0.712  0.710  1.0
  Si  Si10  1  0.000  0.000  0.000  1.0
[/CIF]
.