The structure described by Na2Eu2B2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(6), two equivalent O(3), and two equivalent O(7) atoms. In the second Na site, Na(2) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form distorted face-sharing NaO6 octahedra. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), one O(7), and two equivalent O(4) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(3), one O(5), and one O(7) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Na(1), two equivalent Na(2), one Eu(2), and one B(1) atom. In the second O site, O(4) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form a mixture of edge and corner-sharing OEu4 tetrahedra. In the third O site, O(5) is bonded in a distorted single-bond geometry to one Eu(2), two equivalent Eu(1), and one B(1) atom. In the fourth O site, O(6) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Eu(2), and one B(2) atom. In the fifth O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Na(1), two equivalent Na(2), one Eu(2), and one B(1) atom. In the sixth O site, O(1) is bonded in a distorted single-bond geometry to one Na(1), one Eu(2), two equivalent Eu(1), and one B(2) atom. In the seventh O site, O(2) is bonded in a distorted single-bond geometry to one Eu(2), two equivalent Eu(1), and one B(2) atom. is represented by the CIF card [CIF]
data_Na2Eu2B2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.464
_cell_length_b   10.910
_cell_length_c   10.532
_cell_angle_alpha   117.625
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   657.966
_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
  Na  Na0  1  0.263  0.890  0.953  1.0
  Na  Na1  1  0.737  0.110  0.047  1.0
  Na  Na2  1  0.763  0.110  0.547  1.0
  Na  Na3  1  0.237  0.890  0.453  1.0
  Na  Na4  1  0.943  0.977  0.738  1.0
  Na  Na5  1  0.057  0.023  0.262  1.0
  Na  Na6  1  0.443  0.023  0.762  1.0
  Na  Na7  1  0.557  0.977  0.238  1.0
  Eu  Eu8  1  0.958  0.483  0.682  1.0
  Eu  Eu9  1  0.042  0.517  0.318  1.0
  Eu  Eu10  1  0.458  0.517  0.818  1.0
  Eu  Eu11  1  0.542  0.483  0.182  1.0
  Eu  Eu12  1  0.583  0.686  0.590  1.0
  Eu  Eu13  1  0.417  0.314  0.410  1.0
  Eu  Eu14  1  0.083  0.314  0.910  1.0
  Eu  Eu15  1  0.917  0.686  0.090  1.0
  B  B16  1  0.749  0.817  0.919  1.0
  B  B17  1  0.251  0.183  0.081  1.0
  B  B18  1  0.249  0.183  0.581  1.0
  B  B19  1  0.751  0.817  0.419  1.0
  B  B20  1  0.653  0.291  0.850  1.0
  B  B21  1  0.347  0.709  0.150  1.0
  B  B22  1  0.153  0.709  0.650  1.0
  B  B23  1  0.847  0.291  0.350  1.0
  O  O24  1  0.757  0.347  0.772  1.0
  O  O25  1  0.243  0.653  0.228  1.0
  O  O26  1  0.257  0.653  0.728  1.0
  O  O27  1  0.743  0.347  0.272  1.0
  O  O28  1  0.963  0.652  0.589  1.0
  O  O29  1  0.037  0.348  0.411  1.0
  O  O30  1  0.463  0.348  0.911  1.0
  O  O31  1  0.537  0.652  0.089  1.0
  O  O32  1  0.651  0.873  0.842  1.0
  O  O33  1  0.349  0.127  0.158  1.0
  O  O34  1  0.151  0.127  0.658  1.0
  O  O35  1  0.849  0.873  0.342  1.0
  O  O36  1  0.622  0.474  0.596  1.0
  O  O37  1  0.378  0.526  0.404  1.0
  O  O38  1  0.122  0.526  0.904  1.0
  O  O39  1  0.878  0.474  0.096  1.0
  O  O40  1  0.762  0.673  0.866  1.0
  O  O41  1  0.238  0.327  0.134  1.0
  O  O42  1  0.262  0.327  0.634  1.0
  O  O43  1  0.738  0.673  0.366  1.0
  O  O44  1  0.242  0.817  0.636  1.0
  O  O45  1  0.758  0.183  0.364  1.0
  O  O46  1  0.742  0.183  0.864  1.0
  O  O47  1  0.258  0.817  0.136  1.0
  O  O48  1  0.664  0.897  0.553  1.0
  O  O49  1  0.336  0.103  0.447  1.0
  O  O50  1  0.164  0.103  0.947  1.0
  O  O51  1  0.836  0.897  0.053  1.0
[/CIF]
.
The structure described by Na2Eu2B2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(6), two equivalent O(3), and two equivalent O(7) atoms. In the second Na site, Na(2) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms to form distorted face-sharing NaO6 octahedra. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), one O(7), and two equivalent O(4) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(3), one O(5), and one O(7) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Na(1), two equivalent Na(2), one Eu(2), and one B(1) atom. In the second O site, O(4) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form a mixture of edge and corner-sharing OEu4 tetrahedra. In the third O site, O(5) is bonded in a distorted single-bond geometry to one Eu(2), two equivalent Eu(1), and one B(1) atom. In the fourth O site, O(6) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Eu(2), and one B(2) atom. In the fifth O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Na(1), two equivalent Na(2), one Eu(2), and one B(1) atom. In the sixth O site, O(1) is bonded in a distorted single-bond geometry to one Na(1), one Eu(2), two equivalent Eu(1), and one B(2) atom. In the seventh O site, O(2) is bonded in a distorted single-bond geometry to one Eu(2), two equivalent Eu(1), and one B(2) atom. is represented by the CIF card [CIF]
data_Na2Eu2B2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.464
_cell_length_b   10.910
_cell_length_c   10.532
_cell_angle_alpha   117.625
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   657.966
_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
  Na  Na0  1  0.263  0.890  0.953  1.0
  Na  Na1  1  0.737  0.110  0.047  1.0
  Na  Na2  1  0.763  0.110  0.547  1.0
  Na  Na3  1  0.237  0.890  0.453  1.0
  Na  Na4  1  0.943  0.977  0.738  1.0
  Na  Na5  1  0.057  0.023  0.262  1.0
  Na  Na6  1  0.443  0.023  0.762  1.0
  Na  Na7  1  0.557  0.977  0.238  1.0
  Eu  Eu8  1  0.958  0.483  0.682  1.0
  Eu  Eu9  1  0.042  0.517  0.318  1.0
  Eu  Eu10  1  0.458  0.517  0.818  1.0
  Eu  Eu11  1  0.542  0.483  0.182  1.0
  Eu  Eu12  1  0.583  0.686  0.590  1.0
  Eu  Eu13  1  0.417  0.314  0.410  1.0
  Eu  Eu14  1  0.083  0.314  0.910  1.0
  Eu  Eu15  1  0.917  0.686  0.090  1.0
  B  B16  1  0.749  0.817  0.919  1.0
  B  B17  1  0.251  0.183  0.081  1.0
  B  B18  1  0.249  0.183  0.581  1.0
  B  B19  1  0.751  0.817  0.419  1.0
  B  B20  1  0.653  0.291  0.850  1.0
  B  B21  1  0.347  0.709  0.150  1.0
  B  B22  1  0.153  0.709  0.650  1.0
  B  B23  1  0.847  0.291  0.350  1.0
  O  O24  1  0.757  0.347  0.772  1.0
  O  O25  1  0.243  0.653  0.228  1.0
  O  O26  1  0.257  0.653  0.728  1.0
  O  O27  1  0.743  0.347  0.272  1.0
  O  O28  1  0.963  0.652  0.589  1.0
  O  O29  1  0.037  0.348  0.411  1.0
  O  O30  1  0.463  0.348  0.911  1.0
  O  O31  1  0.537  0.652  0.089  1.0
  O  O32  1  0.651  0.873  0.842  1.0
  O  O33  1  0.349  0.127  0.158  1.0
  O  O34  1  0.151  0.127  0.658  1.0
  O  O35  1  0.849  0.873  0.342  1.0
  O  O36  1  0.622  0.474  0.596  1.0
  O  O37  1  0.378  0.526  0.404  1.0
  O  O38  1  0.122  0.526  0.904  1.0
  O  O39  1  0.878  0.474  0.096  1.0
  O  O40  1  0.762  0.673  0.866  1.0
  O  O41  1  0.238  0.327  0.134  1.0
  O  O42  1  0.262  0.327  0.634  1.0
  O  O43  1  0.738  0.673  0.366  1.0
  O  O44  1  0.242  0.817  0.636  1.0
  O  O45  1  0.758  0.183  0.364  1.0
  O  O46  1  0.742  0.183  0.864  1.0
  O  O47  1  0.258  0.817  0.136  1.0
  O  O48  1  0.664  0.897  0.553  1.0
  O  O49  1  0.336  0.103  0.447  1.0
  O  O50  1  0.164  0.103  0.947  1.0
  O  O51  1  0.836  0.897  0.053  1.0
[/CIF]
.