The compound described by Sm2Pb2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(3), one O(4), one O(5), two equivalent O(2), and two equivalent O(6) atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent Pb(2)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Pb(1)O5 square pyramids,  an edgeedge with one Pb(2)O6 octahedra,  an edgeedge with one Sm(1)O7 pentagonal bipyramid, and  an edgeedge with one Pb(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 40-53°. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form distorted PbO5 square pyramids that share corners with two equivalent Pb(2)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids,  an edgeedge with one Pb(2)O6 octahedra, and  an edgeedge with one Sm(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-44°. In the second Pb site, Pb(2) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms to form distorted PbO6 octahedra that share corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Pb(1)O5 square pyramids,  an edgeedge with one Pb(2)O6 octahedra,  an edgeedge with one Sm(1)O7 pentagonal bipyramid, and  an edgeedge with one Pb(1)O5 square pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Sm(2), one Pb(1), and two equivalent Pb(2) atoms. In the second O site, O(2) is bonded to one Sm(2), two equivalent Sm(1), and one Pb(1) atom to form a mixture of edge and corner-sharing OSm3Pb tetrahedra. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Sm(1), one Sm(2), and one Pb(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sm(1), one Sm(2), one Pb(1), and one Pb(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Sm(1), one Sm(2), and one Pb(2) atom. In the sixth O site, O(6) is bonded to one Sm(2), two equivalent Sm(1), and one Pb(2) atom to form a mixture of edge and corner-sharing OSm3Pb trigonal pyramids. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Sm(2), one Pb(1), and one Pb(2) atom. is represented by the CIF card [CIF]
data_Sm2Pb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.178
_cell_length_b   7.596
_cell_length_c   12.689
_cell_angle_alpha   79.011
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   679.119
_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
  Sm  Sm0  1  0.899  0.528  0.644  1.0
  Sm  Sm1  1  0.399  0.472  0.856  1.0
  Sm  Sm2  1  0.686  0.730  0.387  1.0
  Sm  Sm3  1  0.186  0.270  0.113  1.0
  Sm  Sm4  1  0.814  0.730  0.887  1.0
  Sm  Sm5  1  0.314  0.270  0.613  1.0
  Sm  Sm6  1  0.601  0.528  0.144  1.0
  Sm  Sm7  1  0.101  0.472  0.356  1.0
  Pb  Pb8  1  0.885  0.233  0.898  1.0
  Pb  Pb9  1  0.385  0.767  0.602  1.0
  Pb  Pb10  1  0.111  0.943  0.388  1.0
  Pb  Pb11  1  0.611  0.057  0.112  1.0
  Pb  Pb12  1  0.389  0.943  0.888  1.0
  Pb  Pb13  1  0.889  0.057  0.612  1.0
  Pb  Pb14  1  0.615  0.233  0.398  1.0
  Pb  Pb15  1  0.115  0.767  0.102  1.0
  O  O16  1  0.689  0.002  0.935  1.0
  O  O17  1  0.235  0.531  0.676  1.0
  O  O18  1  0.116  0.393  0.932  1.0
  O  O19  1  0.036  0.785  0.263  1.0
  O  O20  1  0.606  0.802  0.206  1.0
  O  O21  1  0.616  0.607  0.568  1.0
  O  O22  1  0.994  0.682  0.469  1.0
  O  O23  1  0.735  0.469  0.824  1.0
  O  O24  1  0.393  0.844  0.424  1.0
  O  O25  1  0.464  0.785  0.763  1.0
  O  O26  1  0.189  0.998  0.565  1.0
  O  O27  1  0.894  0.802  0.706  1.0
  O  O28  1  0.893  0.156  0.076  1.0
  O  O29  1  0.506  0.682  0.969  1.0
  O  O30  1  0.494  0.318  0.031  1.0
  O  O31  1  0.107  0.844  0.924  1.0
  O  O32  1  0.106  0.198  0.294  1.0
  O  O33  1  0.811  0.002  0.435  1.0
  O  O34  1  0.536  0.215  0.237  1.0
  O  O35  1  0.607  0.156  0.576  1.0
  O  O36  1  0.265  0.531  0.176  1.0
  O  O37  1  0.006  0.318  0.531  1.0
  O  O38  1  0.384  0.393  0.432  1.0
  O  O39  1  0.394  0.198  0.794  1.0
  O  O40  1  0.964  0.215  0.737  1.0
  O  O41  1  0.884  0.607  0.068  1.0
  O  O42  1  0.765  0.469  0.324  1.0
  O  O43  1  0.311  0.998  0.065  1.0
[/CIF]
.
The compound described by Sm2Pb2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(3), one O(4), one O(5), two equivalent O(2), and two equivalent O(6) atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent Pb(2)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Pb(1)O5 square pyramids,  an edgeedge with one Pb(2)O6 octahedra,  an edgeedge with one Sm(1)O7 pentagonal bipyramid, and  an edgeedge with one Pb(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 40-53°. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form distorted PbO5 square pyramids that share corners with two equivalent Pb(2)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids,  an edgeedge with one Pb(2)O6 octahedra, and  an edgeedge with one Sm(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 41-44°. In the second Pb site, Pb(2) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms to form distorted PbO6 octahedra that share corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Pb(1)O5 square pyramids,  an edgeedge with one Pb(2)O6 octahedra,  an edgeedge with one Sm(1)O7 pentagonal bipyramid, and  an edgeedge with one Pb(1)O5 square pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Sm(2), one Pb(1), and two equivalent Pb(2) atoms. In the second O site, O(2) is bonded to one Sm(2), two equivalent Sm(1), and one Pb(1) atom to form a mixture of edge and corner-sharing OSm3Pb tetrahedra. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Sm(1), one Sm(2), and one Pb(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sm(1), one Sm(2), one Pb(1), and one Pb(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Sm(1), one Sm(2), and one Pb(2) atom. In the sixth O site, O(6) is bonded to one Sm(2), two equivalent Sm(1), and one Pb(2) atom to form a mixture of edge and corner-sharing OSm3Pb trigonal pyramids. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Sm(2), one Pb(1), and one Pb(2) atom. is represented by the CIF card [CIF]
data_Sm2Pb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.178
_cell_length_b   7.596
_cell_length_c   12.689
_cell_angle_alpha   79.011
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   679.119
_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
  Sm  Sm0  1  0.899  0.528  0.644  1.0
  Sm  Sm1  1  0.399  0.472  0.856  1.0
  Sm  Sm2  1  0.686  0.730  0.387  1.0
  Sm  Sm3  1  0.186  0.270  0.113  1.0
  Sm  Sm4  1  0.814  0.730  0.887  1.0
  Sm  Sm5  1  0.314  0.270  0.613  1.0
  Sm  Sm6  1  0.601  0.528  0.144  1.0
  Sm  Sm7  1  0.101  0.472  0.356  1.0
  Pb  Pb8  1  0.885  0.233  0.898  1.0
  Pb  Pb9  1  0.385  0.767  0.602  1.0
  Pb  Pb10  1  0.111  0.943  0.388  1.0
  Pb  Pb11  1  0.611  0.057  0.112  1.0
  Pb  Pb12  1  0.389  0.943  0.888  1.0
  Pb  Pb13  1  0.889  0.057  0.612  1.0
  Pb  Pb14  1  0.615  0.233  0.398  1.0
  Pb  Pb15  1  0.115  0.767  0.102  1.0
  O  O16  1  0.689  0.002  0.935  1.0
  O  O17  1  0.235  0.531  0.676  1.0
  O  O18  1  0.116  0.393  0.932  1.0
  O  O19  1  0.036  0.785  0.263  1.0
  O  O20  1  0.606  0.802  0.206  1.0
  O  O21  1  0.616  0.607  0.568  1.0
  O  O22  1  0.994  0.682  0.469  1.0
  O  O23  1  0.735  0.469  0.824  1.0
  O  O24  1  0.393  0.844  0.424  1.0
  O  O25  1  0.464  0.785  0.763  1.0
  O  O26  1  0.189  0.998  0.565  1.0
  O  O27  1  0.894  0.802  0.706  1.0
  O  O28  1  0.893  0.156  0.076  1.0
  O  O29  1  0.506  0.682  0.969  1.0
  O  O30  1  0.494  0.318  0.031  1.0
  O  O31  1  0.107  0.844  0.924  1.0
  O  O32  1  0.106  0.198  0.294  1.0
  O  O33  1  0.811  0.002  0.435  1.0
  O  O34  1  0.536  0.215  0.237  1.0
  O  O35  1  0.607  0.156  0.576  1.0
  O  O36  1  0.265  0.531  0.176  1.0
  O  O37  1  0.006  0.318  0.531  1.0
  O  O38  1  0.384  0.393  0.432  1.0
  O  O39  1  0.394  0.198  0.794  1.0
  O  O40  1  0.964  0.215  0.737  1.0
  O  O41  1  0.884  0.607  0.068  1.0
  O  O42  1  0.765  0.469  0.324  1.0
  O  O43  1  0.311  0.998  0.065  1.0
[/CIF]
.