The material structure described by Mg3Nb6O11 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to six equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(2)O4 tetrahedra and edges with six equivalent Nb(1)O5 square pyramids. In the second Mg site, Mg(2) is bonded to one O(3) and three equivalent O(2) atoms to form MgO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with nine equivalent Nb(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 59°. Nb(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form NbO5 square pyramids that share corners with six equivalent Nb(1)O5 square pyramids, corners with three equivalent Mg(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Nb(1)O5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a square co-planar geometry to four equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal pyramidal geometry to one Mg(2) and three equivalent Nb(1) atoms. is represented by the CIF file [CIF]
data_Mg3Nb6O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.089
_cell_length_b   6.089
_cell_length_c   7.498
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   240.755
_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  0.000  0.000  0.500  1.0
  Mg  Mg1  1  0.333  0.667  0.576  1.0
  Mg  Mg2  1  0.667  0.333  0.424  1.0
  Nb  Nb3  1  0.154  0.846  0.153  1.0
  Nb  Nb4  1  0.154  0.308  0.153  1.0
  Nb  Nb5  1  0.692  0.846  0.153  1.0
  Nb  Nb6  1  0.308  0.154  0.847  1.0
  Nb  Nb7  1  0.846  0.692  0.847  1.0
  Nb  Nb8  1  0.846  0.154  0.847  1.0
  O  O9  1  0.500  0.500  0.000  1.0
  O  O10  1  0.500  0.000  0.000  1.0
  O  O11  1  0.000  0.500  0.000  1.0
  O  O12  1  0.156  0.844  0.672  1.0
  O  O13  1  0.156  0.312  0.672  1.0
  O  O14  1  0.688  0.844  0.672  1.0
  O  O15  1  0.312  0.156  0.328  1.0
  O  O16  1  0.844  0.688  0.328  1.0
  O  O17  1  0.844  0.156  0.328  1.0
  O  O18  1  0.333  0.667  0.313  1.0
  O  O19  1  0.667  0.333  0.687  1.0
[/CIF]
.
The material structure described by Mg3Nb6O11 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to six equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(2)O4 tetrahedra and edges with six equivalent Nb(1)O5 square pyramids. In the second Mg site, Mg(2) is bonded to one O(3) and three equivalent O(2) atoms to form MgO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with nine equivalent Nb(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 59°. Nb(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form NbO5 square pyramids that share corners with six equivalent Nb(1)O5 square pyramids, corners with three equivalent Mg(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Nb(1)O5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a square co-planar geometry to four equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal pyramidal geometry to one Mg(2) and three equivalent Nb(1) atoms. is represented by the CIF file [CIF]
data_Mg3Nb6O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.089
_cell_length_b   6.089
_cell_length_c   7.498
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   240.755
_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  0.000  0.000  0.500  1.0
  Mg  Mg1  1  0.333  0.667  0.576  1.0
  Mg  Mg2  1  0.667  0.333  0.424  1.0
  Nb  Nb3  1  0.154  0.846  0.153  1.0
  Nb  Nb4  1  0.154  0.308  0.153  1.0
  Nb  Nb5  1  0.692  0.846  0.153  1.0
  Nb  Nb6  1  0.308  0.154  0.847  1.0
  Nb  Nb7  1  0.846  0.692  0.847  1.0
  Nb  Nb8  1  0.846  0.154  0.847  1.0
  O  O9  1  0.500  0.500  0.000  1.0
  O  O10  1  0.500  0.000  0.000  1.0
  O  O11  1  0.000  0.500  0.000  1.0
  O  O12  1  0.156  0.844  0.672  1.0
  O  O13  1  0.156  0.312  0.672  1.0
  O  O14  1  0.688  0.844  0.672  1.0
  O  O15  1  0.312  0.156  0.328  1.0
  O  O16  1  0.844  0.688  0.328  1.0
  O  O17  1  0.844  0.156  0.328  1.0
  O  O18  1  0.333  0.667  0.313  1.0
  O  O19  1  0.667  0.333  0.687  1.0
[/CIF]
.