The material described by Nd2Ce2O7 crystallizes in the orthorhombic Pmma space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NdO6 octahedra. The corner-sharing octahedral tilt angles are 68°. In the second Nd site, Nd(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(5), and four equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Nd(1) and two equivalent Ce(1) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with four equivalent O(1)Ce2Nd2 tetrahedra, corners with four equivalent O(4)Ce3Nd tetrahedra, corners with four equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(3)Ce4 tetrahedra, and edges with four equivalent O(2)CeNd3 tetrahedra. In the second O site, O(2) is bonded to one Nd(2), two equivalent Nd(1), and one Ce(1) atom to form distorted OCeNd3 tetrahedra that share corners with two equivalent O(1)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce2Nd2 tetrahedra, corners with two equivalent O(4)Ce3Nd tetrahedra, corners with two equivalent O(3)Ce4 tetrahedra, corners with six equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(4)Ce3Nd tetrahedra,  an edgeedge with one O(2)CeNd3 tetrahedra, and edges with two equivalent O(1)Ce2Nd2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(1)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce2Nd2 tetrahedra, corners with four equivalent O(4)Ce3Nd tetrahedra, corners with four equivalent O(3)Ce4 tetrahedra, corners with four equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(1)Ce2Nd2 tetrahedra,  an edgeedge with one O(5)Ce2Nd2 tetrahedra, and edges with four equivalent O(4)Ce3Nd tetrahedra. In the fourth O site, O(4) is bonded to one Nd(2), one Ce(1), and two equivalent Ce(2) atoms to form OCe3Nd tetrahedra that share corners with two equivalent O(1)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce2Nd2 tetrahedra, corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(2)CeNd3 tetrahedra, corners with six equivalent O(4)Ce3Nd tetrahedra,  an edgeedge with one O(4)Ce3Nd tetrahedra,  an edgeedge with one O(2)CeNd3 tetrahedra, edges with two equivalent O(5)Ce2Nd2 tetrahedra, and edges with two equivalent O(3)Ce4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Nd(2) and two equivalent Ce(2) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with four equivalent O(5)Ce2Nd2 tetrahedra, corners with four equivalent O(4)Ce3Nd tetrahedra, corners with four equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(3)Ce4 tetrahedra, and edges with four equivalent O(4)Ce3Nd tetrahedra. is represented by the CIF file [CIF]
data_Ce2Nd2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.808
_cell_length_b   7.966
_cell_length_c   11.228
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   340.558
_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
  Ce  Ce0  1  0.500  0.750  0.751  1.0
  Ce  Ce1  1  0.500  0.250  0.249  1.0
  Ce  Ce2  1  0.000  0.000  0.000  1.0
  Ce  Ce3  1  0.000  0.500  0.000  1.0
  Nd  Nd4  1  0.000  0.000  0.500  1.0
  Nd  Nd5  1  0.500  0.250  0.772  1.0
  Nd  Nd6  1  0.000  0.500  0.500  1.0
  Nd  Nd7  1  0.500  0.750  0.228  1.0
  O  O8  1  0.000  0.750  0.619  1.0
  O  O9  1  0.500  0.959  0.372  1.0
  O  O10  1  0.000  0.250  0.134  1.0
  O  O11  1  0.500  0.016  0.119  1.0
  O  O12  1  0.500  0.984  0.881  1.0
  O  O13  1  0.500  0.516  0.881  1.0
  O  O14  1  0.000  0.750  0.866  1.0
  O  O15  1  0.000  0.250  0.884  1.0
  O  O16  1  0.500  0.041  0.628  1.0
  O  O17  1  0.500  0.459  0.628  1.0
  O  O18  1  0.500  0.541  0.372  1.0
  O  O19  1  0.000  0.250  0.381  1.0
  O  O20  1  0.000  0.750  0.116  1.0
  O  O21  1  0.500  0.484  0.119  1.0
[/CIF]
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The material described by Nd2Ce2O7 crystallizes in the orthorhombic Pmma space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NdO6 octahedra. The corner-sharing octahedral tilt angles are 68°. In the second Nd site, Nd(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(5), and four equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Nd(1) and two equivalent Ce(1) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with four equivalent O(1)Ce2Nd2 tetrahedra, corners with four equivalent O(4)Ce3Nd tetrahedra, corners with four equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(3)Ce4 tetrahedra, and edges with four equivalent O(2)CeNd3 tetrahedra. In the second O site, O(2) is bonded to one Nd(2), two equivalent Nd(1), and one Ce(1) atom to form distorted OCeNd3 tetrahedra that share corners with two equivalent O(1)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce2Nd2 tetrahedra, corners with two equivalent O(4)Ce3Nd tetrahedra, corners with two equivalent O(3)Ce4 tetrahedra, corners with six equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(4)Ce3Nd tetrahedra,  an edgeedge with one O(2)CeNd3 tetrahedra, and edges with two equivalent O(1)Ce2Nd2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(1)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce2Nd2 tetrahedra, corners with four equivalent O(4)Ce3Nd tetrahedra, corners with four equivalent O(3)Ce4 tetrahedra, corners with four equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(1)Ce2Nd2 tetrahedra,  an edgeedge with one O(5)Ce2Nd2 tetrahedra, and edges with four equivalent O(4)Ce3Nd tetrahedra. In the fourth O site, O(4) is bonded to one Nd(2), one Ce(1), and two equivalent Ce(2) atoms to form OCe3Nd tetrahedra that share corners with two equivalent O(1)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce2Nd2 tetrahedra, corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(2)CeNd3 tetrahedra, corners with six equivalent O(4)Ce3Nd tetrahedra,  an edgeedge with one O(4)Ce3Nd tetrahedra,  an edgeedge with one O(2)CeNd3 tetrahedra, edges with two equivalent O(5)Ce2Nd2 tetrahedra, and edges with two equivalent O(3)Ce4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Nd(2) and two equivalent Ce(2) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with four equivalent O(5)Ce2Nd2 tetrahedra, corners with four equivalent O(4)Ce3Nd tetrahedra, corners with four equivalent O(2)CeNd3 tetrahedra,  an edgeedge with one O(3)Ce4 tetrahedra, and edges with four equivalent O(4)Ce3Nd tetrahedra. is represented by the CIF file [CIF]
data_Ce2Nd2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.808
_cell_length_b   7.966
_cell_length_c   11.228
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   340.558
_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
  Ce  Ce0  1  0.500  0.750  0.751  1.0
  Ce  Ce1  1  0.500  0.250  0.249  1.0
  Ce  Ce2  1  0.000  0.000  0.000  1.0
  Ce  Ce3  1  0.000  0.500  0.000  1.0
  Nd  Nd4  1  0.000  0.000  0.500  1.0
  Nd  Nd5  1  0.500  0.250  0.772  1.0
  Nd  Nd6  1  0.000  0.500  0.500  1.0
  Nd  Nd7  1  0.500  0.750  0.228  1.0
  O  O8  1  0.000  0.750  0.619  1.0
  O  O9  1  0.500  0.959  0.372  1.0
  O  O10  1  0.000  0.250  0.134  1.0
  O  O11  1  0.500  0.016  0.119  1.0
  O  O12  1  0.500  0.984  0.881  1.0
  O  O13  1  0.500  0.516  0.881  1.0
  O  O14  1  0.000  0.750  0.866  1.0
  O  O15  1  0.000  0.250  0.884  1.0
  O  O16  1  0.500  0.041  0.628  1.0
  O  O17  1  0.500  0.459  0.628  1.0
  O  O18  1  0.500  0.541  0.372  1.0
  O  O19  1  0.000  0.250  0.381  1.0
  O  O20  1  0.000  0.750  0.116  1.0
  O  O21  1  0.500  0.484  0.119  1.0
[/CIF]
.