The structure described by Sr11(MgSi5)2 crystallizes in the monoclinic C2/m space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 7-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one Si(4), two equivalent Si(2), and two equivalent Si(5) atoms. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one Si(5), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one Si(2), two equivalent Si(1), and four equivalent Si(4) atoms. In the fifth Sr site, Sr(5) is bonded in a 9-coordinate geometry to three equivalent Mg(1), two equivalent Si(2), two equivalent Si(3), and two equivalent Si(5) atoms. In the sixth Sr site, Sr(6) is bonded in a square co-planar geometry to two equivalent Si(2) and two equivalent Si(5) atoms. Mg(1) is bonded to three equivalent Sr(5), one Si(3), and three equivalent Si(5) atoms to form a mixture of distorted edge and face-sharing MgSr3Si4 tetrahedra. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sr(3), two equivalent Sr(4), three equivalent Sr(1), one Si(3), and one Si(4) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Sr(4), one Sr(6), two equivalent Sr(1), two equivalent Sr(2), two equivalent Sr(5), and one Si(3) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), two equivalent Sr(5), one Mg(1), one Si(1), and one Si(2) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Sr(2), two equivalent Sr(3), four equivalent Sr(4), one Si(1), and one Si(4) atom. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Sr(3), one Sr(6), two equivalent Sr(2), two equivalent Sr(5), and three equivalent Mg(1) atoms. is represented by the CIF file [CIF]
data_Sr11(MgSi5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.152
_cell_length_b   10.152
_cell_length_c   14.903
_cell_angle_alpha   68.455
_cell_angle_beta   68.455
_cell_angle_gamma   27.123
_symmetry_Int_Tables_number   1
_cell_volume   648.361
_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
  Sr  Sr0  1  0.206  0.206  0.622  1.0
  Sr  Sr1  1  0.983  0.983  0.804  1.0
  Sr  Sr2  1  0.356  0.356  0.717  1.0
  Sr  Sr3  1  0.429  0.429  0.441  1.0
  Sr  Sr4  1  0.157  0.157  0.896  1.0
  Sr  Sr5  1  0.794  0.794  0.378  1.0
  Sr  Sr6  1  0.500  0.500  0.000  1.0
  Sr  Sr7  1  0.017  0.017  0.196  1.0
  Sr  Sr8  1  0.843  0.843  0.104  1.0
  Sr  Sr9  1  0.571  0.571  0.559  1.0
  Sr  Sr10  1  0.644  0.644  0.283  1.0
  Mg  Mg11  1  0.220  0.220  0.083  1.0
  Mg  Mg12  1  0.780  0.780  0.917  1.0
  Si  Si13  1  0.831  0.831  0.579  1.0
  Si  Si14  1  0.389  0.389  0.236  1.0
  Si  Si15  1  0.260  0.260  0.253  1.0
  Si  Si16  1  0.046  0.046  0.416  1.0
  Si  Si17  1  0.611  0.611  0.764  1.0
  Si  Si18  1  0.643  0.643  0.070  1.0
  Si  Si19  1  0.169  0.169  0.421  1.0
  Si  Si20  1  0.357  0.357  0.930  1.0
  Si  Si21  1  0.740  0.740  0.747  1.0
  Si  Si22  1  0.954  0.954  0.584  1.0
[/CIF]
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The structure described by Sr11(MgSi5)2 crystallizes in the monoclinic C2/m space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 7-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one Si(4), two equivalent Si(2), and two equivalent Si(5) atoms. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one Si(5), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one Si(2), two equivalent Si(1), and four equivalent Si(4) atoms. In the fifth Sr site, Sr(5) is bonded in a 9-coordinate geometry to three equivalent Mg(1), two equivalent Si(2), two equivalent Si(3), and two equivalent Si(5) atoms. In the sixth Sr site, Sr(6) is bonded in a square co-planar geometry to two equivalent Si(2) and two equivalent Si(5) atoms. Mg(1) is bonded to three equivalent Sr(5), one Si(3), and three equivalent Si(5) atoms to form a mixture of distorted edge and face-sharing MgSr3Si4 tetrahedra. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sr(3), two equivalent Sr(4), three equivalent Sr(1), one Si(3), and one Si(4) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Sr(4), one Sr(6), two equivalent Sr(1), two equivalent Sr(2), two equivalent Sr(5), and one Si(3) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), two equivalent Sr(5), one Mg(1), one Si(1), and one Si(2) atom. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Sr(2), two equivalent Sr(3), four equivalent Sr(4), one Si(1), and one Si(4) atom. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Sr(3), one Sr(6), two equivalent Sr(2), two equivalent Sr(5), and three equivalent Mg(1) atoms. is represented by the CIF file [CIF]
data_Sr11(MgSi5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.152
_cell_length_b   10.152
_cell_length_c   14.903
_cell_angle_alpha   68.455
_cell_angle_beta   68.455
_cell_angle_gamma   27.123
_symmetry_Int_Tables_number   1
_cell_volume   648.361
_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
  Sr  Sr0  1  0.206  0.206  0.622  1.0
  Sr  Sr1  1  0.983  0.983  0.804  1.0
  Sr  Sr2  1  0.356  0.356  0.717  1.0
  Sr  Sr3  1  0.429  0.429  0.441  1.0
  Sr  Sr4  1  0.157  0.157  0.896  1.0
  Sr  Sr5  1  0.794  0.794  0.378  1.0
  Sr  Sr6  1  0.500  0.500  0.000  1.0
  Sr  Sr7  1  0.017  0.017  0.196  1.0
  Sr  Sr8  1  0.843  0.843  0.104  1.0
  Sr  Sr9  1  0.571  0.571  0.559  1.0
  Sr  Sr10  1  0.644  0.644  0.283  1.0
  Mg  Mg11  1  0.220  0.220  0.083  1.0
  Mg  Mg12  1  0.780  0.780  0.917  1.0
  Si  Si13  1  0.831  0.831  0.579  1.0
  Si  Si14  1  0.389  0.389  0.236  1.0
  Si  Si15  1  0.260  0.260  0.253  1.0
  Si  Si16  1  0.046  0.046  0.416  1.0
  Si  Si17  1  0.611  0.611  0.764  1.0
  Si  Si18  1  0.643  0.643  0.070  1.0
  Si  Si19  1  0.169  0.169  0.421  1.0
  Si  Si20  1  0.357  0.357  0.930  1.0
  Si  Si21  1  0.740  0.740  0.747  1.0
  Si  Si22  1  0.954  0.954  0.584  1.0
[/CIF]
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