The material structure described by Rb2MgNb2(TeO6)2 crystallizes in the monoclinic Cm space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(3), two equivalent O(4), and two equivalent O(8) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms. Mg(1) is bonded to one O(1), one O(6), and two equivalent O(4) atoms to form distorted MgO4 tetrahedra that share  a cornercorner with one Te(2)O6 octahedra and corners with two equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 75°. Nb(1) is bonded to one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form NbO5 trigonal bipyramids that share corners with two equivalent Te(2)O6 octahedra,  a cornercorner with one Mg(1)O4 tetrahedra, and corners with two equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 35-38°. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a distorted T-shaped geometry to one O(5) and two equivalent O(4) atoms. In the second Te site, Te(2) is bonded to one O(1), one O(5), two equivalent O(3), and two equivalent O(7) atoms to form TeO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra and corners with four equivalent Nb(1)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Mg(1) and one Te(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Nb(1), and one Te(2) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Rb(1), one Rb(2), one Mg(1), and one Te(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Te(1), and one Te(2) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Rb(1), one Mg(1), and two equivalent Nb(1) atoms. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Rb(2), one Nb(1), and one Te(2) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Rb(1) and one Nb(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Rb2MgNb2(TeO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.503
_cell_length_b   6.988
_cell_length_c   8.396
_cell_angle_alpha   90.000
_cell_angle_beta   61.744
_cell_angle_gamma   117.755
_symmetry_Int_Tables_number   1
_cell_volume   329.094
_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
  Rb  Rb0  1  0.777  0.388  0.355  1.0
  Rb  Rb1  1  0.150  0.575  0.760  1.0
  Mg  Mg2  1  0.456  0.728  0.285  1.0
  Nb  Nb3  1  0.525  0.515  0.928  1.0
  Nb  Nb4  1  0.525  0.011  0.928  1.0
  Te  Te5  1  0.137  0.069  0.498  1.0
  Te  Te6  1  0.991  0.996  0.986  1.0
  O  O7  1  0.775  0.887  0.249  1.0
  O  O8  1  0.539  0.270  0.010  1.0
  O  O9  1  0.191  0.893  0.988  1.0
  O  O10  1  0.326  0.388  0.386  1.0
  O  O11  1  0.191  0.298  0.988  1.0
  O  O12  1  0.326  0.938  0.386  1.0
  O  O13  1  0.207  0.103  0.699  1.0
  O  O14  1  0.392  0.696  0.071  1.0
  O  O15  1  0.804  0.100  0.958  1.0
  O  O16  1  0.683  0.606  0.677  1.0
  O  O17  1  0.804  0.705  0.958  1.0
  O  O18  1  0.683  0.077  0.677  1.0
[/CIF]
.
The material structure described by Rb2MgNb2(TeO6)2 crystallizes in the monoclinic Cm space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(3), two equivalent O(4), and two equivalent O(8) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms. Mg(1) is bonded to one O(1), one O(6), and two equivalent O(4) atoms to form distorted MgO4 tetrahedra that share  a cornercorner with one Te(2)O6 octahedra and corners with two equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 75°. Nb(1) is bonded to one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form NbO5 trigonal bipyramids that share corners with two equivalent Te(2)O6 octahedra,  a cornercorner with one Mg(1)O4 tetrahedra, and corners with two equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 35-38°. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a distorted T-shaped geometry to one O(5) and two equivalent O(4) atoms. In the second Te site, Te(2) is bonded to one O(1), one O(5), two equivalent O(3), and two equivalent O(7) atoms to form TeO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra and corners with four equivalent Nb(1)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Mg(1) and one Te(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Nb(1), and one Te(2) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Rb(1), one Rb(2), one Mg(1), and one Te(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Te(1), and one Te(2) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Rb(1), one Mg(1), and two equivalent Nb(1) atoms. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Rb(2), one Nb(1), and one Te(2) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Rb(1) and one Nb(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Rb2MgNb2(TeO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.503
_cell_length_b   6.988
_cell_length_c   8.396
_cell_angle_alpha   90.000
_cell_angle_beta   61.744
_cell_angle_gamma   117.755
_symmetry_Int_Tables_number   1
_cell_volume   329.094
_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
  Rb  Rb0  1  0.777  0.388  0.355  1.0
  Rb  Rb1  1  0.150  0.575  0.760  1.0
  Mg  Mg2  1  0.456  0.728  0.285  1.0
  Nb  Nb3  1  0.525  0.515  0.928  1.0
  Nb  Nb4  1  0.525  0.011  0.928  1.0
  Te  Te5  1  0.137  0.069  0.498  1.0
  Te  Te6  1  0.991  0.996  0.986  1.0
  O  O7  1  0.775  0.887  0.249  1.0
  O  O8  1  0.539  0.270  0.010  1.0
  O  O9  1  0.191  0.893  0.988  1.0
  O  O10  1  0.326  0.388  0.386  1.0
  O  O11  1  0.191  0.298  0.988  1.0
  O  O12  1  0.326  0.938  0.386  1.0
  O  O13  1  0.207  0.103  0.699  1.0
  O  O14  1  0.392  0.696  0.071  1.0
  O  O15  1  0.804  0.100  0.958  1.0
  O  O16  1  0.683  0.606  0.677  1.0
  O  O17  1  0.804  0.705  0.958  1.0
  O  O18  1  0.683  0.077  0.677  1.0
[/CIF]
.