The crystal structure described by Sr2YFe2GaO7 crystallizes in the monoclinic Cc space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(7), and three equivalent O(6) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(4), two equivalent O(5), and three equivalent O(3) atoms. Y(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO5 square pyramids that share corners with four equivalent Fe(1)O5 square pyramids and  a cornercorner with one Ga(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(6), two equivalent O(1), and two equivalent O(7) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra and corners with four equivalent Fe(2)O5 trigonal bipyramids. Ga(1) is bonded to one O(3), one O(6), and two equivalent O(2) atoms to form GaO4 tetrahedra that share  a cornercorner with one Fe(1)O5 square pyramid, corners with two equivalent Ga(1)O4 tetrahedra, and  a cornercorner with one Fe(2)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 4-coordinate geometry to three equivalent Sr(1), one Fe(2), and one Ga(1) atom. In the second O site, O(7) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Fe(2) atoms. In the third O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Fe(2) atoms. In the fourth O site, O(2) is bonded to one Sr(1), one Sr(2), and two equivalent Ga(1) atoms to form distorted OSr2Ga2 tetrahedra that share corners with two equivalent O(5)Sr2Y2Fe2 octahedra and corners with two equivalent O(2)Sr2Ga2 tetrahedra. The corner-sharing octahedral tilt angles range from 16-49°. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Sr(2), one Fe(1), and one Ga(1) atom. In the sixth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Sr(2), two equivalent Y(1), and two equivalent Fe(1) atoms. In the seventh O site, O(5) is bonded to two equivalent Sr(2), two equivalent Y(1), and two equivalent Fe(1) atoms to form distorted OSr2Y2Fe2 octahedra that share corners with two equivalent O(2)Sr2Ga2 tetrahedra and faces with two equivalent O(5)Sr2Y2Fe2 octahedra. is represented by the CIF file [CIF]
data_Sr2YGaFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.024
_cell_length_b   12.024
_cell_length_c   5.598
_cell_angle_alpha   76.564
_cell_angle_beta   76.564
_cell_angle_gamma   27.602
_symmetry_Int_Tables_number   1
_cell_volume   364.107
_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  0.126  0.673  0.840  1.0
  Sr  Sr1  1  0.873  0.318  0.140  1.0
  Sr  Sr2  1  0.673  0.126  0.340  1.0
  Sr  Sr3  1  0.318  0.873  0.640  1.0
  Y  Y4  1  0.499  0.001  0.491  1.0
  Y  Y5  1  0.001  0.499  0.991  1.0
  Ga  Ga6  1  0.675  0.319  0.712  1.0
  Ga  Ga7  1  0.319  0.675  0.212  1.0
  Fe  Fe8  1  0.923  0.429  0.566  1.0
  Fe  Fe9  1  0.574  0.080  0.916  1.0
  Fe  Fe10  1  0.429  0.923  0.066  1.0
  Fe  Fe11  1  0.080  0.574  0.416  1.0
  O  O12  1  0.797  0.825  0.685  1.0
  O  O13  1  0.619  0.376  0.371  1.0
  O  O14  1  0.825  0.797  0.185  1.0
  O  O15  1  0.261  0.877  0.212  1.0
  O  O16  1  0.690  0.676  0.817  1.0
  O  O17  1  0.676  0.690  0.317  1.0
  O  O18  1  0.376  0.619  0.871  1.0
  O  O19  1  0.178  0.192  0.305  1.0
  O  O20  1  0.192  0.178  0.805  1.0
  O  O21  1  0.877  0.261  0.712  1.0
  O  O22  1  0.728  0.119  0.852  1.0
  O  O23  1  0.119  0.728  0.352  1.0
  O  O24  1  0.300  0.324  0.683  1.0
  O  O25  1  0.324  0.300  0.183  1.0
[/CIF]
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The crystal structure described by Sr2YFe2GaO7 crystallizes in the monoclinic Cc space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(7), and three equivalent O(6) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(4), two equivalent O(5), and three equivalent O(3) atoms. Y(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO5 square pyramids that share corners with four equivalent Fe(1)O5 square pyramids and  a cornercorner with one Ga(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(6), two equivalent O(1), and two equivalent O(7) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra and corners with four equivalent Fe(2)O5 trigonal bipyramids. Ga(1) is bonded to one O(3), one O(6), and two equivalent O(2) atoms to form GaO4 tetrahedra that share  a cornercorner with one Fe(1)O5 square pyramid, corners with two equivalent Ga(1)O4 tetrahedra, and  a cornercorner with one Fe(2)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 4-coordinate geometry to three equivalent Sr(1), one Fe(2), and one Ga(1) atom. In the second O site, O(7) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Fe(2) atoms. In the third O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Fe(2) atoms. In the fourth O site, O(2) is bonded to one Sr(1), one Sr(2), and two equivalent Ga(1) atoms to form distorted OSr2Ga2 tetrahedra that share corners with two equivalent O(5)Sr2Y2Fe2 octahedra and corners with two equivalent O(2)Sr2Ga2 tetrahedra. The corner-sharing octahedral tilt angles range from 16-49°. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Sr(2), one Fe(1), and one Ga(1) atom. In the sixth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Sr(2), two equivalent Y(1), and two equivalent Fe(1) atoms. In the seventh O site, O(5) is bonded to two equivalent Sr(2), two equivalent Y(1), and two equivalent Fe(1) atoms to form distorted OSr2Y2Fe2 octahedra that share corners with two equivalent O(2)Sr2Ga2 tetrahedra and faces with two equivalent O(5)Sr2Y2Fe2 octahedra. is represented by the CIF file [CIF]
data_Sr2YGaFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.024
_cell_length_b   12.024
_cell_length_c   5.598
_cell_angle_alpha   76.564
_cell_angle_beta   76.564
_cell_angle_gamma   27.602
_symmetry_Int_Tables_number   1
_cell_volume   364.107
_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  0.126  0.673  0.840  1.0
  Sr  Sr1  1  0.873  0.318  0.140  1.0
  Sr  Sr2  1  0.673  0.126  0.340  1.0
  Sr  Sr3  1  0.318  0.873  0.640  1.0
  Y  Y4  1  0.499  0.001  0.491  1.0
  Y  Y5  1  0.001  0.499  0.991  1.0
  Ga  Ga6  1  0.675  0.319  0.712  1.0
  Ga  Ga7  1  0.319  0.675  0.212  1.0
  Fe  Fe8  1  0.923  0.429  0.566  1.0
  Fe  Fe9  1  0.574  0.080  0.916  1.0
  Fe  Fe10  1  0.429  0.923  0.066  1.0
  Fe  Fe11  1  0.080  0.574  0.416  1.0
  O  O12  1  0.797  0.825  0.685  1.0
  O  O13  1  0.619  0.376  0.371  1.0
  O  O14  1  0.825  0.797  0.185  1.0
  O  O15  1  0.261  0.877  0.212  1.0
  O  O16  1  0.690  0.676  0.817  1.0
  O  O17  1  0.676  0.690  0.317  1.0
  O  O18  1  0.376  0.619  0.871  1.0
  O  O19  1  0.178  0.192  0.305  1.0
  O  O20  1  0.192  0.178  0.805  1.0
  O  O21  1  0.877  0.261  0.712  1.0
  O  O22  1  0.728  0.119  0.852  1.0
  O  O23  1  0.119  0.728  0.352  1.0
  O  O24  1  0.300  0.324  0.683  1.0
  O  O25  1  0.324  0.300  0.183  1.0
[/CIF]
.