The material structure described by Sr4Ti5(Si2O11)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to one O(4), one O(6), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(7) atoms. In the second Sr site, Sr(2) is bonded in a 10-coordinate geometry to one O(4), one O(6), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(8) atoms. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and edges with two equivalent Ti(1)O6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(7) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with four equivalent Si(2)O4 tetrahedra. In the third Ti site, Ti(3) is bonded in a 5-coordinate geometry to one O(5) and four equivalent O(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(7), one O(8), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-50°. In the second Si site, Si(2) is bonded to one O(6), one O(8), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(2)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. There are eight inequivalent O sites. In the first O site, O(6) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Si(2) atom. In the second O site, O(7) is bonded in a distorted bent 150 degrees geometry to two equivalent Sr(1), one Ti(2), and one Si(1) atom. In the third O site, O(8) is bonded in a distorted linear geometry to two equivalent Sr(2), one Si(1), and one Si(2) atom. In the fourth O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Ti(1), and one Si(1) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Ti(2), and one Si(2) atom. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), and two equivalent Ti(3) atoms. In the seventh O site, O(4) is bonded in a distorted L-shaped geometry to one Sr(1), one Sr(2), and two equivalent Ti(1) atoms. In the eighth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr4Ti5(Si2O11)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.618
_cell_length_b   7.618
_cell_length_c   12.008
_cell_angle_alpha   67.412
_cell_angle_beta   67.412
_cell_angle_gamma   43.800
_symmetry_Int_Tables_number   1
_cell_volume   439.048
_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  0.954  0.954  0.740  1.0
  Sr  Sr1  1  0.765  0.765  0.267  1.0
  Sr  Sr2  1  0.046  0.046  0.260  1.0
  Sr  Sr3  1  0.235  0.235  0.733  1.0
  Ti  Ti4  1  0.242  0.758  0.000  1.0
  Ti  Ti5  1  0.500  0.500  0.500  1.0
  Ti  Ti6  1  0.725  0.725  0.001  1.0
  Ti  Ti7  1  0.758  0.242  0.000  1.0
  Ti  Ti8  1  0.275  0.275  0.999  1.0
  Si  Si9  1  0.594  0.594  0.729  1.0
  Si  Si10  1  0.158  0.158  0.453  1.0
  Si  Si11  1  0.842  0.842  0.547  1.0
  Si  Si12  1  0.406  0.406  0.271  1.0
  O  O13  1  0.672  0.202  0.182  1.0
  O  O14  1  0.866  0.345  0.418  1.0
  O  O15  1  0.655  0.134  0.582  1.0
  O  O16  1  0.458  0.958  0.118  1.0
  O  O17  1  0.908  0.908  0.000  1.0
  O  O18  1  0.405  0.405  0.001  1.0
  O  O19  1  0.147  0.147  0.591  1.0
  O  O20  1  0.853  0.853  0.409  1.0
  O  O21  1  0.798  0.328  0.818  1.0
  O  O22  1  0.469  0.469  0.357  1.0
  O  O23  1  0.328  0.798  0.818  1.0
  O  O24  1  0.279  0.279  0.345  1.0
  O  O25  1  0.542  0.042  0.882  1.0
  O  O26  1  0.595  0.595  0.999  1.0
  O  O27  1  0.042  0.542  0.882  1.0
  O  O28  1  0.531  0.531  0.643  1.0
  O  O29  1  0.092  0.092  1.000  1.0
  O  O30  1  0.958  0.458  0.118  1.0
  O  O31  1  0.134  0.655  0.582  1.0
  O  O32  1  0.721  0.721  0.655  1.0
  O  O33  1  0.345  0.866  0.418  1.0
  O  O34  1  0.202  0.672  0.182  1.0
[/CIF]
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The material structure described by Sr4Ti5(Si2O11)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to one O(4), one O(6), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(7) atoms. In the second Sr site, Sr(2) is bonded in a 10-coordinate geometry to one O(4), one O(6), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(8) atoms. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and edges with two equivalent Ti(1)O6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(7) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with four equivalent Si(2)O4 tetrahedra. In the third Ti site, Ti(3) is bonded in a 5-coordinate geometry to one O(5) and four equivalent O(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(7), one O(8), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-50°. In the second Si site, Si(2) is bonded to one O(6), one O(8), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(2)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. There are eight inequivalent O sites. In the first O site, O(6) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one Si(2) atom. In the second O site, O(7) is bonded in a distorted bent 150 degrees geometry to two equivalent Sr(1), one Ti(2), and one Si(1) atom. In the third O site, O(8) is bonded in a distorted linear geometry to two equivalent Sr(2), one Si(1), and one Si(2) atom. In the fourth O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Ti(1), and one Si(1) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Ti(2), and one Si(2) atom. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), and two equivalent Ti(3) atoms. In the seventh O site, O(4) is bonded in a distorted L-shaped geometry to one Sr(1), one Sr(2), and two equivalent Ti(1) atoms. In the eighth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr4Ti5(Si2O11)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.618
_cell_length_b   7.618
_cell_length_c   12.008
_cell_angle_alpha   67.412
_cell_angle_beta   67.412
_cell_angle_gamma   43.800
_symmetry_Int_Tables_number   1
_cell_volume   439.048
_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  0.954  0.954  0.740  1.0
  Sr  Sr1  1  0.765  0.765  0.267  1.0
  Sr  Sr2  1  0.046  0.046  0.260  1.0
  Sr  Sr3  1  0.235  0.235  0.733  1.0
  Ti  Ti4  1  0.242  0.758  0.000  1.0
  Ti  Ti5  1  0.500  0.500  0.500  1.0
  Ti  Ti6  1  0.725  0.725  0.001  1.0
  Ti  Ti7  1  0.758  0.242  0.000  1.0
  Ti  Ti8  1  0.275  0.275  0.999  1.0
  Si  Si9  1  0.594  0.594  0.729  1.0
  Si  Si10  1  0.158  0.158  0.453  1.0
  Si  Si11  1  0.842  0.842  0.547  1.0
  Si  Si12  1  0.406  0.406  0.271  1.0
  O  O13  1  0.672  0.202  0.182  1.0
  O  O14  1  0.866  0.345  0.418  1.0
  O  O15  1  0.655  0.134  0.582  1.0
  O  O16  1  0.458  0.958  0.118  1.0
  O  O17  1  0.908  0.908  0.000  1.0
  O  O18  1  0.405  0.405  0.001  1.0
  O  O19  1  0.147  0.147  0.591  1.0
  O  O20  1  0.853  0.853  0.409  1.0
  O  O21  1  0.798  0.328  0.818  1.0
  O  O22  1  0.469  0.469  0.357  1.0
  O  O23  1  0.328  0.798  0.818  1.0
  O  O24  1  0.279  0.279  0.345  1.0
  O  O25  1  0.542  0.042  0.882  1.0
  O  O26  1  0.595  0.595  0.999  1.0
  O  O27  1  0.042  0.542  0.882  1.0
  O  O28  1  0.531  0.531  0.643  1.0
  O  O29  1  0.092  0.092  1.000  1.0
  O  O30  1  0.958  0.458  0.118  1.0
  O  O31  1  0.134  0.655  0.582  1.0
  O  O32  1  0.721  0.721  0.655  1.0
  O  O33  1  0.345  0.866  0.418  1.0
  O  O34  1  0.202  0.672  0.182  1.0
[/CIF]
.