The material structure described by SrAl2(SiO5)2 crystallizes in the monoclinic P2_1/m space group. Sr(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra and edges with two equivalent Al(2)O6 octahedra. In the second Al site, Al(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra and edges with two equivalent Al(1)O6 octahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-58°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sr(1), one Al(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Sr(1), one Al(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Al(1), one Al(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Al(1) and one Al(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to two equivalent Sr(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrAl2(SiO5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.187
_cell_length_b   5.386
_cell_length_c   5.441
_cell_angle_alpha   66.294
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   353.883
_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
  Sr  Sr0  1  0.750  0.321  0.343  1.0
  Sr  Sr1  1  0.250  0.679  0.657  1.0
  Al  Al2  1  0.000  0.000  0.500  1.0
  Al  Al3  1  0.500  0.000  0.500  1.0
  Al  Al4  1  0.000  0.500  0.000  1.0
  Al  Al5  1  0.500  0.500  0.000  1.0
  Si  Si6  1  0.128  0.010  0.026  1.0
  Si  Si7  1  0.628  0.990  0.974  1.0
  Si  Si8  1  0.872  0.990  0.974  1.0
  Si  Si9  1  0.372  0.010  0.026  1.0
  O  O10  1  0.750  0.054  0.008  1.0
  O  O11  1  0.250  0.946  0.992  1.0
  O  O12  1  0.110  0.339  0.899  1.0
  O  O13  1  0.610  0.661  0.101  1.0
  O  O14  1  0.890  0.661  0.101  1.0
  O  O15  1  0.390  0.339  0.899  1.0
  O  O16  1  0.397  0.875  0.346  1.0
  O  O17  1  0.897  0.125  0.654  1.0
  O  O18  1  0.603  0.125  0.654  1.0
  O  O19  1  0.103  0.875  0.346  1.0
  O  O20  1  0.072  0.855  0.855  1.0
  O  O21  1  0.572  0.145  0.145  1.0
  O  O22  1  0.928  0.145  0.145  1.0
  O  O23  1  0.428  0.855  0.855  1.0
  O  O24  1  0.062  0.348  0.345  1.0
  O  O25  1  0.562  0.652  0.655  1.0
  O  O26  1  0.938  0.652  0.655  1.0
  O  O27  1  0.438  0.348  0.345  1.0
  O  O28  1  0.750  0.714  0.543  1.0
  O  O29  1  0.250  0.286  0.457  1.0
[/CIF]
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The material structure described by SrAl2(SiO5)2 crystallizes in the monoclinic P2_1/m space group. Sr(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra and edges with two equivalent Al(2)O6 octahedra. In the second Al site, Al(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra and edges with two equivalent Al(1)O6 octahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(2)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-58°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sr(1), one Al(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Sr(1), one Al(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Al(1), one Al(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Al(1) and one Al(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to two equivalent Sr(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrAl2(SiO5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.187
_cell_length_b   5.386
_cell_length_c   5.441
_cell_angle_alpha   66.294
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   353.883
_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
  Sr  Sr0  1  0.750  0.321  0.343  1.0
  Sr  Sr1  1  0.250  0.679  0.657  1.0
  Al  Al2  1  0.000  0.000  0.500  1.0
  Al  Al3  1  0.500  0.000  0.500  1.0
  Al  Al4  1  0.000  0.500  0.000  1.0
  Al  Al5  1  0.500  0.500  0.000  1.0
  Si  Si6  1  0.128  0.010  0.026  1.0
  Si  Si7  1  0.628  0.990  0.974  1.0
  Si  Si8  1  0.872  0.990  0.974  1.0
  Si  Si9  1  0.372  0.010  0.026  1.0
  O  O10  1  0.750  0.054  0.008  1.0
  O  O11  1  0.250  0.946  0.992  1.0
  O  O12  1  0.110  0.339  0.899  1.0
  O  O13  1  0.610  0.661  0.101  1.0
  O  O14  1  0.890  0.661  0.101  1.0
  O  O15  1  0.390  0.339  0.899  1.0
  O  O16  1  0.397  0.875  0.346  1.0
  O  O17  1  0.897  0.125  0.654  1.0
  O  O18  1  0.603  0.125  0.654  1.0
  O  O19  1  0.103  0.875  0.346  1.0
  O  O20  1  0.072  0.855  0.855  1.0
  O  O21  1  0.572  0.145  0.145  1.0
  O  O22  1  0.928  0.145  0.145  1.0
  O  O23  1  0.428  0.855  0.855  1.0
  O  O24  1  0.062  0.348  0.345  1.0
  O  O25  1  0.562  0.652  0.655  1.0
  O  O26  1  0.938  0.652  0.655  1.0
  O  O27  1  0.438  0.348  0.345  1.0
  O  O28  1  0.750  0.714  0.543  1.0
  O  O29  1  0.250  0.286  0.457  1.0
[/CIF]
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