The compound described by Sr2YCr2AlO7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Y(1) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(3) atoms. Cr(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form CrO5 square pyramids that share corners with four equivalent Cr(1)O5 square pyramids and  a cornercorner with one Al(1)O4 tetrahedra. Al(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form AlO4 tetrahedra that share corners with two equivalent Cr(1)O5 square pyramids and corners with two equivalent Al(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Cr(1), and one Al(1) atom. In the second O site, O(1) is bonded to two equivalent Sr(1) and two equivalent Al(1) atoms to form distorted corner-sharing OSr2Al2 tetrahedra. In the third O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cr(1) atoms. In the fourth O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cr(1) atoms. is represented by the CIF file [CIF]
data_Sr2YAlCr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.570
_cell_length_b   12.002
_cell_length_c   5.737
_cell_angle_alpha   76.172
_cell_angle_beta   90.000
_cell_angle_gamma   76.583
_symmetry_Int_Tables_number   1
_cell_volume   361.647
_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  0.166  0.688  0.181  1.0
  Sr  Sr1  1  0.854  0.312  0.819  1.0
  Sr  Sr2  1  0.354  0.312  0.369  1.0
  Sr  Sr3  1  0.666  0.688  0.631  1.0
  Y  Y4  1  0.510  1.000  0.500  1.0
  Y  Y5  1  0.010  1.000  0.000  1.0
  Al  Al6  1  0.244  0.500  0.825  1.0
  Al  Al7  1  0.744  0.500  0.175  1.0
  Cr  Cr8  1  0.942  0.152  0.422  1.0
  Cr  Cr9  1  0.094  0.848  0.578  1.0
  Cr  Cr10  1  0.594  0.848  0.074  1.0
  Cr  Cr11  1  0.441  0.152  0.926  1.0
  O  O12  1  0.431  0.500  0.085  1.0
  O  O13  1  0.931  0.500  0.915  1.0
  O  O14  1  0.296  0.871  0.279  1.0
  O  O15  1  0.167  0.129  0.721  1.0
  O  O16  1  0.667  0.129  0.650  1.0
  O  O17  1  0.796  0.871  0.350  1.0
  O  O18  1  0.880  0.860  0.861  1.0
  O  O19  1  0.740  0.140  0.139  1.0
  O  O20  1  0.240  0.140  0.221  1.0
  O  O21  1  0.380  0.860  0.779  1.0
  O  O22  1  0.230  0.637  0.620  1.0
  O  O23  1  0.867  0.363  0.380  1.0
  O  O24  1  0.367  0.363  0.757  1.0
  O  O25  1  0.730  0.637  0.243  1.0
[/CIF]
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The compound described by Sr2YCr2AlO7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Y(1) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(3) atoms. Cr(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form CrO5 square pyramids that share corners with four equivalent Cr(1)O5 square pyramids and  a cornercorner with one Al(1)O4 tetrahedra. Al(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form AlO4 tetrahedra that share corners with two equivalent Cr(1)O5 square pyramids and corners with two equivalent Al(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Cr(1), and one Al(1) atom. In the second O site, O(1) is bonded to two equivalent Sr(1) and two equivalent Al(1) atoms to form distorted corner-sharing OSr2Al2 tetrahedra. In the third O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cr(1) atoms. In the fourth O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cr(1) atoms. is represented by the CIF file [CIF]
data_Sr2YAlCr2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.570
_cell_length_b   12.002
_cell_length_c   5.737
_cell_angle_alpha   76.172
_cell_angle_beta   90.000
_cell_angle_gamma   76.583
_symmetry_Int_Tables_number   1
_cell_volume   361.647
_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  0.166  0.688  0.181  1.0
  Sr  Sr1  1  0.854  0.312  0.819  1.0
  Sr  Sr2  1  0.354  0.312  0.369  1.0
  Sr  Sr3  1  0.666  0.688  0.631  1.0
  Y  Y4  1  0.510  1.000  0.500  1.0
  Y  Y5  1  0.010  1.000  0.000  1.0
  Al  Al6  1  0.244  0.500  0.825  1.0
  Al  Al7  1  0.744  0.500  0.175  1.0
  Cr  Cr8  1  0.942  0.152  0.422  1.0
  Cr  Cr9  1  0.094  0.848  0.578  1.0
  Cr  Cr10  1  0.594  0.848  0.074  1.0
  Cr  Cr11  1  0.441  0.152  0.926  1.0
  O  O12  1  0.431  0.500  0.085  1.0
  O  O13  1  0.931  0.500  0.915  1.0
  O  O14  1  0.296  0.871  0.279  1.0
  O  O15  1  0.167  0.129  0.721  1.0
  O  O16  1  0.667  0.129  0.650  1.0
  O  O17  1  0.796  0.871  0.350  1.0
  O  O18  1  0.880  0.860  0.861  1.0
  O  O19  1  0.740  0.140  0.139  1.0
  O  O20  1  0.240  0.140  0.221  1.0
  O  O21  1  0.380  0.860  0.779  1.0
  O  O22  1  0.230  0.637  0.620  1.0
  O  O23  1  0.867  0.363  0.380  1.0
  O  O24  1  0.367  0.363  0.757  1.0
  O  O25  1  0.730  0.637  0.243  1.0
[/CIF]
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