The structure described by Ba4Ce2O7 crystallizes in the orthorhombic Cmce space group. Ba(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), and five equivalent O(1) atoms. Ce(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form corner-sharing CeO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to five equivalent Ba(1) and one Ce(1) atom to form distorted OBa5Ce octahedra that share corners with three equivalent O(2)Ba4Ce2 octahedra, corners with five equivalent O(1)Ba5Ce octahedra, corners with three equivalent O(3)Ba2Ce2 tetrahedra, edges with eight equivalent O(1)Ba5Ce octahedra, edges with two equivalent O(3)Ba2Ce2 tetrahedra, and  a faceface with one O(2)Ba4Ce2 octahedra. The corner-sharing octahedral tilt angles range from 4-62°. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Ce(1) atoms to form OBa4Ce2 octahedra that share corners with twelve equivalent O(1)Ba5Ce octahedra, corners with four equivalent O(3)Ba2Ce2 tetrahedra, edges with two equivalent O(3)Ba2Ce2 tetrahedra, and faces with four equivalent O(1)Ba5Ce octahedra. The corner-sharing octahedral tilt angles range from 40-62°. In the third O site, O(3) is bonded to two equivalent Ba(1) and two equivalent Ce(1) atoms to form distorted OBa2Ce2 tetrahedra that share corners with two equivalent O(2)Ba4Ce2 octahedra, corners with six equivalent O(1)Ba5Ce octahedra, corners with two equivalent O(3)Ba2Ce2 tetrahedra,  an edgeedge with one O(2)Ba4Ce2 octahedra, and edges with four equivalent O(1)Ba5Ce octahedra. The corner-sharing octahedral tilt angles range from 18-75°. is represented by the CIF file [CIF]
data_Ba4Ce2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.768
_cell_length_b   7.768
_cell_length_c   12.262
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   132.893
_symmetry_Int_Tables_number   1
_cell_volume   542.073
_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
  Ba  Ba0  1  0.629  0.937  0.880  1.0
  Ba  Ba1  1  0.563  0.871  0.380  1.0
  Ba  Ba2  1  0.937  0.629  0.880  1.0
  Ba  Ba3  1  0.129  0.437  0.620  1.0
  Ba  Ba4  1  0.871  0.563  0.380  1.0
  Ba  Ba5  1  0.063  0.371  0.120  1.0
  Ba  Ba6  1  0.437  0.129  0.620  1.0
  Ba  Ba7  1  0.371  0.063  0.120  1.0
  Ce  Ce8  1  0.769  0.769  0.631  1.0
  Ce  Ce9  1  0.731  0.731  0.131  1.0
  Ce  Ce10  1  0.269  0.269  0.869  1.0
  Ce  Ce11  1  0.231  0.231  0.369  1.0
  O  O12  1  0.596  0.920  0.618  1.0
  O  O13  1  0.580  0.904  0.118  1.0
  O  O14  1  0.000  0.000  0.000  1.0
  O  O15  1  0.901  0.901  0.289  1.0
  O  O16  1  0.096  0.420  0.882  1.0
  O  O17  1  0.920  0.596  0.618  1.0
  O  O18  1  0.080  0.404  0.382  1.0
  O  O19  1  0.904  0.580  0.118  1.0
  O  O20  1  0.599  0.599  0.789  1.0
  O  O21  1  0.500  0.500  0.500  1.0
  O  O22  1  0.401  0.401  0.211  1.0
  O  O23  1  0.420  0.096  0.882  1.0
  O  O24  1  0.404  0.080  0.382  1.0
  O  O25  1  0.099  0.099  0.711  1.0
[/CIF]
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The structure described by Ba4Ce2O7 crystallizes in the orthorhombic Cmce space group. Ba(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), and five equivalent O(1) atoms. Ce(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form corner-sharing CeO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to five equivalent Ba(1) and one Ce(1) atom to form distorted OBa5Ce octahedra that share corners with three equivalent O(2)Ba4Ce2 octahedra, corners with five equivalent O(1)Ba5Ce octahedra, corners with three equivalent O(3)Ba2Ce2 tetrahedra, edges with eight equivalent O(1)Ba5Ce octahedra, edges with two equivalent O(3)Ba2Ce2 tetrahedra, and  a faceface with one O(2)Ba4Ce2 octahedra. The corner-sharing octahedral tilt angles range from 4-62°. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Ce(1) atoms to form OBa4Ce2 octahedra that share corners with twelve equivalent O(1)Ba5Ce octahedra, corners with four equivalent O(3)Ba2Ce2 tetrahedra, edges with two equivalent O(3)Ba2Ce2 tetrahedra, and faces with four equivalent O(1)Ba5Ce octahedra. The corner-sharing octahedral tilt angles range from 40-62°. In the third O site, O(3) is bonded to two equivalent Ba(1) and two equivalent Ce(1) atoms to form distorted OBa2Ce2 tetrahedra that share corners with two equivalent O(2)Ba4Ce2 octahedra, corners with six equivalent O(1)Ba5Ce octahedra, corners with two equivalent O(3)Ba2Ce2 tetrahedra,  an edgeedge with one O(2)Ba4Ce2 octahedra, and edges with four equivalent O(1)Ba5Ce octahedra. The corner-sharing octahedral tilt angles range from 18-75°. is represented by the CIF file [CIF]
data_Ba4Ce2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.768
_cell_length_b   7.768
_cell_length_c   12.262
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   132.893
_symmetry_Int_Tables_number   1
_cell_volume   542.073
_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
  Ba  Ba0  1  0.629  0.937  0.880  1.0
  Ba  Ba1  1  0.563  0.871  0.380  1.0
  Ba  Ba2  1  0.937  0.629  0.880  1.0
  Ba  Ba3  1  0.129  0.437  0.620  1.0
  Ba  Ba4  1  0.871  0.563  0.380  1.0
  Ba  Ba5  1  0.063  0.371  0.120  1.0
  Ba  Ba6  1  0.437  0.129  0.620  1.0
  Ba  Ba7  1  0.371  0.063  0.120  1.0
  Ce  Ce8  1  0.769  0.769  0.631  1.0
  Ce  Ce9  1  0.731  0.731  0.131  1.0
  Ce  Ce10  1  0.269  0.269  0.869  1.0
  Ce  Ce11  1  0.231  0.231  0.369  1.0
  O  O12  1  0.596  0.920  0.618  1.0
  O  O13  1  0.580  0.904  0.118  1.0
  O  O14  1  0.000  0.000  0.000  1.0
  O  O15  1  0.901  0.901  0.289  1.0
  O  O16  1  0.096  0.420  0.882  1.0
  O  O17  1  0.920  0.596  0.618  1.0
  O  O18  1  0.080  0.404  0.382  1.0
  O  O19  1  0.904  0.580  0.118  1.0
  O  O20  1  0.599  0.599  0.789  1.0
  O  O21  1  0.500  0.500  0.500  1.0
  O  O22  1  0.401  0.401  0.211  1.0
  O  O23  1  0.420  0.096  0.882  1.0
  O  O24  1  0.404  0.080  0.382  1.0
  O  O25  1  0.099  0.099  0.711  1.0
[/CIF]
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