The compound described by Sr2TiCu2AlO7 crystallizes in the triclinic P1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to one O(1), one O(11), one O(13), one O(3), and one O(7) atom. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one O(12), one O(2), one O(4), one O(8), and two equivalent O(14) atoms. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one O(11), one O(13), one O(2), one O(5), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(14), one O(4), one O(6), and two equivalent O(12) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(11), one O(14), and one O(2) atom to form corner-sharing TiO4 tetrahedra. In the second Ti site, Ti(2) is bonded to one O(1), one O(12), one O(13), and one O(2) atom to form corner-sharing TiO4 tetrahedra. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(3), one O(5), one O(7), and one O(9) atom. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(10), one O(4), one O(6), and one O(8) atom. In the third Cu site, Cu(3) is bonded in a rectangular see-saw-like geometry to one O(3), one O(5), one O(7), and one O(9) atom. In the fourth Cu site, Cu(4) is bonded in a rectangular see-saw-like geometry to one O(10), one O(4), one O(6), and one O(8) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a tetrahedral geometry to one O(10), one O(5), one O(6), and one O(9) atom. In the second Al site, Al(2) is bonded in a tetrahedral geometry to one O(3), one O(4), one O(7), and one O(8) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(4), one Ti(1), and one Ti(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(3), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Cu(1), one Cu(3), and one Al(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Cu(2), one Cu(4), and one Al(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Sr(3), one Cu(1), one Cu(3), and one Al(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sr(4), one Cu(2), one Cu(4), and one Al(1) atom. In the seventh O site, O(7) is bonded to one Sr(1), one Cu(1), one Cu(3), and one Al(2) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the eighth O site, O(8) is bonded to one Sr(2), one Cu(2), one Cu(4), and one Al(2) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the ninth O site, O(9) is bonded to one Sr(3), one Cu(1), one Cu(3), and one Al(1) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the tenth O site, O(10) is bonded to one Sr(4), one Cu(2), one Cu(4), and one Al(1) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one Ti(1) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Sr(2), two equivalent Sr(4), and one Ti(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one Ti(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(4), two equivalent Sr(2), and one Ti(1) atom. is represented by the CIF card [CIF]
data_Sr2TiAlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.431
_cell_length_b   5.745
_cell_length_c   12.100
_cell_angle_alpha   103.794
_cell_angle_beta   102.991
_cell_angle_gamma   89.992
_symmetry_Int_Tables_number   1
_cell_volume   356.721
_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  0.362  0.334  0.721  1.0
  Sr  Sr1  1  0.637  0.671  0.280  1.0
  Sr  Sr2  1  0.863  0.890  0.721  1.0
  Sr  Sr3  1  0.138  0.109  0.280  1.0
  Ti  Ti4  1  0.281  0.676  0.500  1.0
  Ti  Ti5  1  0.781  0.326  0.500  1.0
  Al  Al6  1  0.984  0.993  0.001  1.0
  Al  Al7  1  0.483  0.511  0.000  1.0
  Cu  Cu8  1  0.434  0.944  0.890  1.0
  Cu  Cu9  1  0.539  0.070  0.111  1.0
  Cu  Cu10  1  0.934  0.450  0.890  1.0
  Cu  Cu11  1  0.039  0.543  0.110  1.0
  O  O12  1  0.128  0.380  0.501  1.0
  O  O13  1  0.627  0.622  0.500  1.0
  O  O14  1  0.251  0.285  0.893  1.0
  O  O15  1  0.346  0.723  0.108  1.0
  O  O16  1  0.752  0.111  0.893  1.0
  O  O17  1  0.846  0.889  0.108  1.0
  O  O18  1  0.612  0.610  0.889  1.0
  O  O19  1  0.712  0.399  0.110  1.0
  O  O20  1  0.113  0.783  0.890  1.0
  O  O21  1  0.212  0.215  0.111  1.0
  O  O22  1  0.268  0.882  0.634  1.0
  O  O23  1  0.634  0.121  0.367  1.0
  O  O24  1  0.770  0.256  0.635  1.0
  O  O25  1  0.132  0.746  0.367  1.0
[/CIF]
.
The compound described by Sr2TiCu2AlO7 crystallizes in the triclinic P1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to one O(1), one O(11), one O(13), one O(3), and one O(7) atom. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one O(12), one O(2), one O(4), one O(8), and two equivalent O(14) atoms. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one O(11), one O(13), one O(2), one O(5), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(14), one O(4), one O(6), and two equivalent O(12) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(11), one O(14), and one O(2) atom to form corner-sharing TiO4 tetrahedra. In the second Ti site, Ti(2) is bonded to one O(1), one O(12), one O(13), and one O(2) atom to form corner-sharing TiO4 tetrahedra. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one O(3), one O(5), one O(7), and one O(9) atom. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(10), one O(4), one O(6), and one O(8) atom. In the third Cu site, Cu(3) is bonded in a rectangular see-saw-like geometry to one O(3), one O(5), one O(7), and one O(9) atom. In the fourth Cu site, Cu(4) is bonded in a rectangular see-saw-like geometry to one O(10), one O(4), one O(6), and one O(8) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a tetrahedral geometry to one O(10), one O(5), one O(6), and one O(9) atom. In the second Al site, Al(2) is bonded in a tetrahedral geometry to one O(3), one O(4), one O(7), and one O(8) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(4), one Ti(1), and one Ti(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(3), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Cu(1), one Cu(3), and one Al(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Cu(2), one Cu(4), and one Al(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Sr(3), one Cu(1), one Cu(3), and one Al(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sr(4), one Cu(2), one Cu(4), and one Al(1) atom. In the seventh O site, O(7) is bonded to one Sr(1), one Cu(1), one Cu(3), and one Al(2) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the eighth O site, O(8) is bonded to one Sr(2), one Cu(2), one Cu(4), and one Al(2) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the ninth O site, O(9) is bonded to one Sr(3), one Cu(1), one Cu(3), and one Al(1) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the tenth O site, O(10) is bonded to one Sr(4), one Cu(2), one Cu(4), and one Al(1) atom to form distorted corner-sharing OSrAlCu2 trigonal pyramids. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one Ti(1) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Sr(2), two equivalent Sr(4), and one Ti(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(3), and one Ti(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(4), two equivalent Sr(2), and one Ti(1) atom. is represented by the CIF card [CIF]
data_Sr2TiAlCu2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.431
_cell_length_b   5.745
_cell_length_c   12.100
_cell_angle_alpha   103.794
_cell_angle_beta   102.991
_cell_angle_gamma   89.992
_symmetry_Int_Tables_number   1
_cell_volume   356.721
_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  0.362  0.334  0.721  1.0
  Sr  Sr1  1  0.637  0.671  0.280  1.0
  Sr  Sr2  1  0.863  0.890  0.721  1.0
  Sr  Sr3  1  0.138  0.109  0.280  1.0
  Ti  Ti4  1  0.281  0.676  0.500  1.0
  Ti  Ti5  1  0.781  0.326  0.500  1.0
  Al  Al6  1  0.984  0.993  0.001  1.0
  Al  Al7  1  0.483  0.511  0.000  1.0
  Cu  Cu8  1  0.434  0.944  0.890  1.0
  Cu  Cu9  1  0.539  0.070  0.111  1.0
  Cu  Cu10  1  0.934  0.450  0.890  1.0
  Cu  Cu11  1  0.039  0.543  0.110  1.0
  O  O12  1  0.128  0.380  0.501  1.0
  O  O13  1  0.627  0.622  0.500  1.0
  O  O14  1  0.251  0.285  0.893  1.0
  O  O15  1  0.346  0.723  0.108  1.0
  O  O16  1  0.752  0.111  0.893  1.0
  O  O17  1  0.846  0.889  0.108  1.0
  O  O18  1  0.612  0.610  0.889  1.0
  O  O19  1  0.712  0.399  0.110  1.0
  O  O20  1  0.113  0.783  0.890  1.0
  O  O21  1  0.212  0.215  0.111  1.0
  O  O22  1  0.268  0.882  0.634  1.0
  O  O23  1  0.634  0.121  0.367  1.0
  O  O24  1  0.770  0.256  0.635  1.0
  O  O25  1  0.132  0.746  0.367  1.0
[/CIF]
.