The compound described by Eu3NbO7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Eu site, Eu(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(2) atoms to form distorted EuO7 pentagonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Eu(2)O7 pentagonal bipyramids, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-44°. In the third Eu site, Eu(3) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. Nb(1) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Eu(2)O7 pentagonal bipyramids, and edges with two equivalent Eu(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Eu(1) and two equivalent Eu(3) atoms to form OEu4 tetrahedra that share corners with two equivalent O(5)Eu3Nb tetrahedra, corners with two equivalent O(7)Eu3Nb tetrahedra, corners with two equivalent O(2)Eu4 tetrahedra, corners with four equivalent O(1)Eu4 tetrahedra,  an edgeedge with one O(5)Eu3Nb tetrahedra,  an edgeedge with one O(7)Eu3Nb tetrahedra, and  an edgeedge with one O(2)Eu4 tetrahedra. In the second O site, O(2) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(5)Eu3Nb tetrahedra, corners with two equivalent O(7)Eu3Nb tetrahedra, corners with two equivalent O(1)Eu4 tetrahedra, corners with four equivalent O(2)Eu4 tetrahedra,  an edgeedge with one O(5)Eu3Nb tetrahedra,  an edgeedge with one O(7)Eu3Nb tetrahedra, and  an edgeedge with one O(1)Eu4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Eu(2), one Eu(3), and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Eu(2), one Eu(3), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one Eu(1), one Eu(2), one Eu(3), and one Nb(1) atom to form distorted OEu3Nb tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with two equivalent O(2)Eu4 tetrahedra,  an edgeedge with one O(1)Eu4 tetrahedra,  an edgeedge with one O(2)Eu4 tetrahedra, and edges with two equivalent O(7)Eu3Nb tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), and one Nb(1) atom. In the seventh O site, O(7) is bonded to one Eu(1), one Eu(2), one Eu(3), and one Nb(1) atom to form distorted OEu3Nb tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with two equivalent O(2)Eu4 tetrahedra,  an edgeedge with one O(1)Eu4 tetrahedra,  an edgeedge with one O(2)Eu4 tetrahedra, and edges with two equivalent O(5)Eu3Nb tetrahedra. is represented by the CIF file [CIF]
data_Eu3NbO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.488
_cell_length_b   7.691
_cell_length_c   10.824
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   623.420
_cell_formula_units_Z   4
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
  Eu  Eu0  1  0.023  0.506  0.744  1.0
  Eu  Eu1  1  0.205  0.750  0.014  1.0
  Eu  Eu2  1  0.214  0.744  0.476  1.0
  Eu  Eu3  1  0.286  0.256  0.976  1.0
  Eu  Eu4  1  0.295  0.250  0.514  1.0
  Eu  Eu5  1  0.477  0.494  0.244  1.0
  Eu  Eu6  1  0.523  0.994  0.256  1.0
  Eu  Eu7  1  0.705  0.750  0.986  1.0
  Eu  Eu8  1  0.714  0.756  0.524  1.0
  Eu  Eu9  1  0.786  0.244  0.024  1.0
  Eu  Eu10  1  0.795  0.250  0.486  1.0
  Eu  Eu11  1  0.977  0.006  0.756  1.0
  Nb  Nb12  1  0.006  0.996  0.249  1.0
  Nb  Nb13  1  0.494  0.004  0.749  1.0
  Nb  Nb14  1  0.506  0.504  0.751  1.0
  Nb  Nb15  1  0.994  0.496  0.251  1.0
  O  O16  1  0.013  0.261  0.877  1.0
  O  O17  1  0.036  0.245  0.607  1.0
  O  O18  1  0.076  0.752  0.243  1.0
  O  O19  1  0.146  0.044  0.103  1.0
  O  O20  1  0.190  0.471  0.119  1.0
  O  O21  1  0.200  0.038  0.369  1.0
  O  O22  1  0.211  0.459  0.369  1.0
  O  O23  1  0.289  0.541  0.869  1.0
  O  O24  1  0.300  0.962  0.869  1.0
  O  O25  1  0.310  0.529  0.619  1.0
  O  O26  1  0.354  0.956  0.603  1.0
  O  O27  1  0.424  0.248  0.743  1.0
  O  O28  1  0.464  0.755  0.107  1.0
  O  O29  1  0.487  0.739  0.377  1.0
  O  O30  1  0.513  0.239  0.123  1.0
  O  O31  1  0.536  0.255  0.393  1.0
  O  O32  1  0.576  0.748  0.757  1.0
  O  O33  1  0.646  0.456  0.897  1.0
  O  O34  1  0.690  0.029  0.881  1.0
  O  O35  1  0.700  0.462  0.631  1.0
  O  O36  1  0.711  0.041  0.631  1.0
  O  O37  1  0.789  0.959  0.131  1.0
  O  O38  1  0.800  0.538  0.131  1.0
  O  O39  1  0.810  0.971  0.381  1.0
  O  O40  1  0.854  0.544  0.397  1.0
  O  O41  1  0.924  0.252  0.257  1.0
  O  O42  1  0.964  0.745  0.893  1.0
  O  O43  1  0.987  0.761  0.623  1.0
[/CIF]
.
The compound described by Eu3NbO7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Eu site, Eu(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(2) atoms to form distorted EuO7 pentagonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Eu(2)O7 pentagonal bipyramids, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-44°. In the third Eu site, Eu(3) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. Nb(1) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Eu(2)O7 pentagonal bipyramids, and edges with two equivalent Eu(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Eu(1) and two equivalent Eu(3) atoms to form OEu4 tetrahedra that share corners with two equivalent O(5)Eu3Nb tetrahedra, corners with two equivalent O(7)Eu3Nb tetrahedra, corners with two equivalent O(2)Eu4 tetrahedra, corners with four equivalent O(1)Eu4 tetrahedra,  an edgeedge with one O(5)Eu3Nb tetrahedra,  an edgeedge with one O(7)Eu3Nb tetrahedra, and  an edgeedge with one O(2)Eu4 tetrahedra. In the second O site, O(2) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(5)Eu3Nb tetrahedra, corners with two equivalent O(7)Eu3Nb tetrahedra, corners with two equivalent O(1)Eu4 tetrahedra, corners with four equivalent O(2)Eu4 tetrahedra,  an edgeedge with one O(5)Eu3Nb tetrahedra,  an edgeedge with one O(7)Eu3Nb tetrahedra, and  an edgeedge with one O(1)Eu4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Eu(2), one Eu(3), and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Eu(2), one Eu(3), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one Eu(1), one Eu(2), one Eu(3), and one Nb(1) atom to form distorted OEu3Nb tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with two equivalent O(2)Eu4 tetrahedra,  an edgeedge with one O(1)Eu4 tetrahedra,  an edgeedge with one O(2)Eu4 tetrahedra, and edges with two equivalent O(7)Eu3Nb tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), and one Nb(1) atom. In the seventh O site, O(7) is bonded to one Eu(1), one Eu(2), one Eu(3), and one Nb(1) atom to form distorted OEu3Nb tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with two equivalent O(2)Eu4 tetrahedra,  an edgeedge with one O(1)Eu4 tetrahedra,  an edgeedge with one O(2)Eu4 tetrahedra, and edges with two equivalent O(5)Eu3Nb tetrahedra. is represented by the CIF file [CIF]
data_Eu3NbO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.488
_cell_length_b   7.691
_cell_length_c   10.824
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   623.420
_cell_formula_units_Z   4
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
  Eu  Eu0  1  0.023  0.506  0.744  1.0
  Eu  Eu1  1  0.205  0.750  0.014  1.0
  Eu  Eu2  1  0.214  0.744  0.476  1.0
  Eu  Eu3  1  0.286  0.256  0.976  1.0
  Eu  Eu4  1  0.295  0.250  0.514  1.0
  Eu  Eu5  1  0.477  0.494  0.244  1.0
  Eu  Eu6  1  0.523  0.994  0.256  1.0
  Eu  Eu7  1  0.705  0.750  0.986  1.0
  Eu  Eu8  1  0.714  0.756  0.524  1.0
  Eu  Eu9  1  0.786  0.244  0.024  1.0
  Eu  Eu10  1  0.795  0.250  0.486  1.0
  Eu  Eu11  1  0.977  0.006  0.756  1.0
  Nb  Nb12  1  0.006  0.996  0.249  1.0
  Nb  Nb13  1  0.494  0.004  0.749  1.0
  Nb  Nb14  1  0.506  0.504  0.751  1.0
  Nb  Nb15  1  0.994  0.496  0.251  1.0
  O  O16  1  0.013  0.261  0.877  1.0
  O  O17  1  0.036  0.245  0.607  1.0
  O  O18  1  0.076  0.752  0.243  1.0
  O  O19  1  0.146  0.044  0.103  1.0
  O  O20  1  0.190  0.471  0.119  1.0
  O  O21  1  0.200  0.038  0.369  1.0
  O  O22  1  0.211  0.459  0.369  1.0
  O  O23  1  0.289  0.541  0.869  1.0
  O  O24  1  0.300  0.962  0.869  1.0
  O  O25  1  0.310  0.529  0.619  1.0
  O  O26  1  0.354  0.956  0.603  1.0
  O  O27  1  0.424  0.248  0.743  1.0
  O  O28  1  0.464  0.755  0.107  1.0
  O  O29  1  0.487  0.739  0.377  1.0
  O  O30  1  0.513  0.239  0.123  1.0
  O  O31  1  0.536  0.255  0.393  1.0
  O  O32  1  0.576  0.748  0.757  1.0
  O  O33  1  0.646  0.456  0.897  1.0
  O  O34  1  0.690  0.029  0.881  1.0
  O  O35  1  0.700  0.462  0.631  1.0
  O  O36  1  0.711  0.041  0.631  1.0
  O  O37  1  0.789  0.959  0.131  1.0
  O  O38  1  0.800  0.538  0.131  1.0
  O  O39  1  0.810  0.971  0.381  1.0
  O  O40  1  0.854  0.544  0.397  1.0
  O  O41  1  0.924  0.252  0.257  1.0
  O  O42  1  0.964  0.745  0.893  1.0
  O  O43  1  0.987  0.761  0.623  1.0
[/CIF]
.