The material structure described by Pb3MgNb2O9 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(4), one O(6), and two equivalent O(9) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(8) atoms to form NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-12°. In the second Nb site, Nb(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(7) atoms to form NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. There are three inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 5-coordinate geometry to one O(9), two equivalent O(1), and two equivalent O(4) atoms. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one O(2), one O(6), and one O(9) atom. In the third Pb site, Pb(3) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(6), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Mg(1), one Nb(2), and two equivalent Pb(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(1), one Pb(2), and one Pb(3) atom. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Mg(1), one Nb(2), one Pb(3), and two equivalent Pb(1) atoms. In the fifth O site, O(5) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Mg(1), one Nb(1), one Pb(2), and one Pb(3) atom. In the seventh O site, O(7) is bonded in a linear geometry to two equivalent Nb(2) atoms. In the eighth O site, O(8) is bonded in a distorted linear geometry to two equivalent Nb(1) atoms. In the ninth O site, O(9) is bonded to two equivalent Mg(1), one Pb(1), one Pb(2), and one Pb(3) atom to form distorted corner-sharing OMg2Pb3 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgNb2(PbO3)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.127
_cell_length_b   5.785
_cell_length_c   9.211
_cell_angle_alpha   71.894
_cell_angle_beta   89.431
_cell_angle_gamma   89.650
_symmetry_Int_Tables_number   1
_cell_volume   208.999
_cell_formula_units_Z   1
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
  Mg  Mg0  1  0.482  0.481  0.007  1.0
  Nb  Nb1  1  0.453  0.820  0.348  1.0
  Nb  Nb2  1  0.522  0.163  0.669  1.0
  Pb  Pb3  1  0.997  0.627  0.729  1.0
  Pb  Pb4  1  0.948  0.338  0.287  1.0
  Pb  Pb5  1  0.898  0.943  0.015  1.0
  O  O6  1  0.497  0.339  0.822  1.0
  O  O7  1  0.518  0.665  0.179  1.0
  O  O8  1  0.497  0.990  0.505  1.0
  O  O9  1  0.504  0.842  0.829  1.0
  O  O10  1  0.497  0.492  0.500  1.0
  O  O11  1  0.515  0.148  0.184  1.0
  O  O12  1  0.994  0.162  0.668  1.0
  O  O13  1  0.994  0.825  0.338  1.0
  O  O14  1  0.989  0.518  0.004  1.0
[/CIF]
.
The material structure described by Pb3MgNb2O9 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(4), one O(6), and two equivalent O(9) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(8) atoms to form NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-12°. In the second Nb site, Nb(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(7) atoms to form NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. There are three inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 5-coordinate geometry to one O(9), two equivalent O(1), and two equivalent O(4) atoms. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one O(2), one O(6), and one O(9) atom. In the third Pb site, Pb(3) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(6), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Mg(1), one Nb(2), and two equivalent Pb(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(1), one Pb(2), and one Pb(3) atom. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Mg(1), one Nb(2), one Pb(3), and two equivalent Pb(1) atoms. In the fifth O site, O(5) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Mg(1), one Nb(1), one Pb(2), and one Pb(3) atom. In the seventh O site, O(7) is bonded in a linear geometry to two equivalent Nb(2) atoms. In the eighth O site, O(8) is bonded in a distorted linear geometry to two equivalent Nb(1) atoms. In the ninth O site, O(9) is bonded to two equivalent Mg(1), one Pb(1), one Pb(2), and one Pb(3) atom to form distorted corner-sharing OMg2Pb3 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgNb2(PbO3)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.127
_cell_length_b   5.785
_cell_length_c   9.211
_cell_angle_alpha   71.894
_cell_angle_beta   89.431
_cell_angle_gamma   89.650
_symmetry_Int_Tables_number   1
_cell_volume   208.999
_cell_formula_units_Z   1
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
  Mg  Mg0  1  0.482  0.481  0.007  1.0
  Nb  Nb1  1  0.453  0.820  0.348  1.0
  Nb  Nb2  1  0.522  0.163  0.669  1.0
  Pb  Pb3  1  0.997  0.627  0.729  1.0
  Pb  Pb4  1  0.948  0.338  0.287  1.0
  Pb  Pb5  1  0.898  0.943  0.015  1.0
  O  O6  1  0.497  0.339  0.822  1.0
  O  O7  1  0.518  0.665  0.179  1.0
  O  O8  1  0.497  0.990  0.505  1.0
  O  O9  1  0.504  0.842  0.829  1.0
  O  O10  1  0.497  0.492  0.500  1.0
  O  O11  1  0.515  0.148  0.184  1.0
  O  O12  1  0.994  0.162  0.668  1.0
  O  O13  1  0.994  0.825  0.338  1.0
  O  O14  1  0.989  0.518  0.004  1.0
[/CIF]
.