The compound described by Mg2La3NbO9 crystallizes in the orthorhombic Immm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and faces with four equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the third Mg site, Mg(3) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, and faces with four equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. There are two inequivalent La sites. In the first La site, La(1) is bonded to two equivalent O(1), two equivalent O(2), four equivalent O(3), and four equivalent O(5) atoms to form distorted LaO12 cuboctahedra that share corners with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, faces with two equivalent Mg(1)O6 octahedra, faces with two equivalent Mg(2)O6 octahedra, faces with two equivalent Mg(3)O6 octahedra, and faces with two equivalent Nb(1)O6 octahedra. In the second La site, La(2) is bonded in a 12-coordinate geometry to one O(1), two equivalent O(3), two equivalent O(5), three equivalent O(2), and four equivalent O(4) atoms. Nb(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-12°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(3), two equivalent La(1), and two equivalent La(2) atoms to form a mixture of distorted corner and face-sharing OLa4Mg2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Mg(2), one La(1), three equivalent La(2), and one Nb(1) atom. In the third O site, O(3) is bonded to one Mg(2), one Mg(3), two equivalent La(1), and two equivalent La(2) atoms to form a mixture of distorted edge, corner, and face-sharing OLa4Mg2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Mg(2), four equivalent La(2), and one Nb(1) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Mg(1), two equivalent La(1), two equivalent La(2), and one Nb(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_La3Mg2NbO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.847
_cell_length_b   9.847
_cell_length_c   9.847
_cell_angle_alpha   146.636
_cell_angle_beta   131.979
_cell_angle_gamma   59.731
_symmetry_Int_Tables_number   1
_cell_volume   386.843
_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
  La  La0  1  0.721  0.500  0.221  1.0
  La  La1  1  0.414  0.148  0.266  1.0
  La  La2  1  0.119  0.852  0.266  1.0
  La  La3  1  0.279  0.500  0.779  1.0
  La  La4  1  0.881  0.148  0.734  1.0
  La  La5  1  0.586  0.852  0.734  1.0
  Mg  Mg6  1  0.000  0.000  0.000  1.0
  Mg  Mg7  1  0.668  0.668  0.000  1.0
  Mg  Mg8  1  0.332  0.332  0.000  1.0
  Mg  Mg9  1  0.500  0.000  0.500  1.0
  Nb  Nb10  1  0.169  0.669  0.500  1.0
  Nb  Nb11  1  0.831  0.331  0.500  1.0
  O  O12  1  0.751  0.000  0.751  1.0
  O  O13  1  0.403  0.656  0.748  1.0
  O  O14  1  0.092  0.344  0.748  1.0
  O  O15  1  0.582  0.832  0.250  1.0
  O  O16  1  0.254  0.517  0.263  1.0
  O  O17  1  0.911  0.150  0.239  1.0
  O  O18  1  0.418  0.668  0.250  1.0
  O  O19  1  0.089  0.328  0.239  1.0
  O  O20  1  0.746  0.009  0.263  1.0
  O  O21  1  0.249  0.000  0.249  1.0
  O  O22  1  0.908  0.656  0.252  1.0
  O  O23  1  0.597  0.344  0.252  1.0
  O  O24  1  0.418  0.168  0.750  1.0
  O  O25  1  0.089  0.850  0.761  1.0
  O  O26  1  0.746  0.483  0.737  1.0
  O  O27  1  0.582  0.332  0.750  1.0
  O  O28  1  0.254  0.991  0.737  1.0
  O  O29  1  0.911  0.672  0.761  1.0
[/CIF]
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The compound described by Mg2La3NbO9 crystallizes in the orthorhombic Immm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and faces with four equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the third Mg site, Mg(3) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, and faces with four equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. There are two inequivalent La sites. In the first La site, La(1) is bonded to two equivalent O(1), two equivalent O(2), four equivalent O(3), and four equivalent O(5) atoms to form distorted LaO12 cuboctahedra that share corners with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, faces with two equivalent Mg(1)O6 octahedra, faces with two equivalent Mg(2)O6 octahedra, faces with two equivalent Mg(3)O6 octahedra, and faces with two equivalent Nb(1)O6 octahedra. In the second La site, La(2) is bonded in a 12-coordinate geometry to one O(1), two equivalent O(3), two equivalent O(5), three equivalent O(2), and four equivalent O(4) atoms. Nb(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-12°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(3), two equivalent La(1), and two equivalent La(2) atoms to form a mixture of distorted corner and face-sharing OLa4Mg2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Mg(2), one La(1), three equivalent La(2), and one Nb(1) atom. In the third O site, O(3) is bonded to one Mg(2), one Mg(3), two equivalent La(1), and two equivalent La(2) atoms to form a mixture of distorted edge, corner, and face-sharing OLa4Mg2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Mg(2), four equivalent La(2), and one Nb(1) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Mg(1), two equivalent La(1), two equivalent La(2), and one Nb(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_La3Mg2NbO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.847
_cell_length_b   9.847
_cell_length_c   9.847
_cell_angle_alpha   146.636
_cell_angle_beta   131.979
_cell_angle_gamma   59.731
_symmetry_Int_Tables_number   1
_cell_volume   386.843
_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
  La  La0  1  0.721  0.500  0.221  1.0
  La  La1  1  0.414  0.148  0.266  1.0
  La  La2  1  0.119  0.852  0.266  1.0
  La  La3  1  0.279  0.500  0.779  1.0
  La  La4  1  0.881  0.148  0.734  1.0
  La  La5  1  0.586  0.852  0.734  1.0
  Mg  Mg6  1  0.000  0.000  0.000  1.0
  Mg  Mg7  1  0.668  0.668  0.000  1.0
  Mg  Mg8  1  0.332  0.332  0.000  1.0
  Mg  Mg9  1  0.500  0.000  0.500  1.0
  Nb  Nb10  1  0.169  0.669  0.500  1.0
  Nb  Nb11  1  0.831  0.331  0.500  1.0
  O  O12  1  0.751  0.000  0.751  1.0
  O  O13  1  0.403  0.656  0.748  1.0
  O  O14  1  0.092  0.344  0.748  1.0
  O  O15  1  0.582  0.832  0.250  1.0
  O  O16  1  0.254  0.517  0.263  1.0
  O  O17  1  0.911  0.150  0.239  1.0
  O  O18  1  0.418  0.668  0.250  1.0
  O  O19  1  0.089  0.328  0.239  1.0
  O  O20  1  0.746  0.009  0.263  1.0
  O  O21  1  0.249  0.000  0.249  1.0
  O  O22  1  0.908  0.656  0.252  1.0
  O  O23  1  0.597  0.344  0.252  1.0
  O  O24  1  0.418  0.168  0.750  1.0
  O  O25  1  0.089  0.850  0.761  1.0
  O  O26  1  0.746  0.483  0.737  1.0
  O  O27  1  0.582  0.332  0.750  1.0
  O  O28  1  0.254  0.991  0.737  1.0
  O  O29  1  0.911  0.672  0.761  1.0
[/CIF]
.