The material described by Mg14YNbO16 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Y(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, edges with four equivalent Mg(3)O6 octahedra, and edges with four equivalent Mg(4)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to one O(4), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Y(1)O6 octahedra, and edges with four equivalent Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the third Mg site, Mg(3) is bonded to one O(5), one O(6), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the fourth Mg site, Mg(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Mg(4)O6 octahedra,  an edgeedge with one Y(1)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. Y(1) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form YO6 octahedra that share corners with two equivalent Y(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(4)O6 octahedra, and edges with eight equivalent Mg(2)O6 octahedra. The corner-sharing octahedra are not tilted. Nb(1) is bonded to two equivalent O(6) and four equivalent O(2) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(4)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Y(1) atom to form OYMg5 octahedra that share corners with two equivalent O(2)Mg5Nb octahedra, corners with four equivalent O(1)YMg5 octahedra, edges with two equivalent O(2)Mg5Nb octahedra, edges with two equivalent O(5)Mg6 octahedra, edges with two equivalent O(4)Y2Mg4 octahedra, edges with two equivalent O(1)YMg5 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second O site, O(2) is bonded to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), and one Nb(1) atom to form OMg5Nb octahedra that share corners with two equivalent O(1)YMg5 octahedra, corners with four equivalent O(2)Mg5Nb octahedra, edges with two equivalent O(6)Mg4Nb2 octahedra, edges with two equivalent O(2)Mg5Nb octahedra, edges with two equivalent O(5)Mg6 octahedra, edges with two equivalent O(1)YMg5 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the third O site, O(3) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms to form OMg6 octahedra that share corners with six equivalent O(3)Mg6 octahedra,  an edgeedge with one O(6)Mg4Nb2 octahedra,  an edgeedge with one O(4)Y2Mg4 octahedra, edges with two equivalent O(5)Mg6 octahedra, edges with four equivalent O(2)Mg5Nb octahedra, and edges with four equivalent O(1)YMg5 octahedra. The corner-sharing octahedral tilt angles range from 1-7°. In the fourth O site, O(4) is bonded to four equivalent Mg(2) and two equivalent Y(1) atoms to form OY2Mg4 octahedra that share corners with two equivalent O(4)Y2Mg4 octahedra, corners with four equivalent O(5)Mg6 octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with eight equivalent O(1)YMg5 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(6)Mg4Nb2 octahedra, corners with two equivalent O(5)Mg6 octahedra, corners with two equivalent O(4)Y2Mg4 octahedra, edges with four equivalent O(2)Mg5Nb octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with four equivalent O(1)YMg5 octahedra. The corner-sharing octahedra are not tilted. In the sixth O site, O(6) is bonded to four equivalent Mg(3) and two equivalent Nb(1) atoms to form OMg4Nb2 octahedra that share corners with two equivalent O(6)Mg4Nb2 octahedra, corners with four equivalent O(5)Mg6 octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with eight equivalent O(2)Mg5Nb octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_YMg14NbO16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.742
_cell_length_b   8.742
_cell_length_c   4.414
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   337.273
_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
  Y  Y0  1  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.000  0.500  0.000  1.0
  Mg  Mg3  1  0.263  0.000  0.500  1.0
  Mg  Mg4  1  0.737  0.000  0.500  1.0
  Mg  Mg5  1  0.249  0.500  0.500  1.0
  Mg  Mg6  1  0.751  0.500  0.500  1.0
  Mg  Mg7  1  0.000  0.263  0.500  1.0
  Mg  Mg8  1  0.500  0.249  0.500  1.0
  Mg  Mg9  1  0.000  0.737  0.500  1.0
  Mg  Mg10  1  0.500  0.751  0.500  1.0
  Mg  Mg11  1  0.256  0.256  0.000  1.0
  Mg  Mg12  1  0.744  0.256  0.000  1.0
  Mg  Mg13  1  0.256  0.744  0.000  1.0
  Mg  Mg14  1  0.744  0.744  0.000  1.0
  Nb  Nb15  1  0.500  0.500  0.000  1.0
  O  O16  1  0.000  0.257  0.000  1.0
  O  O17  1  0.500  0.237  0.000  1.0
  O  O18  1  0.000  0.743  0.000  1.0
  O  O19  1  0.500  0.763  0.000  1.0
  O  O20  1  0.248  0.248  0.500  1.0
  O  O21  1  0.752  0.248  0.500  1.0
  O  O22  1  0.248  0.752  0.500  1.0
  O  O23  1  0.752  0.752  0.500  1.0
  O  O24  1  0.000  0.000  0.500  1.0
  O  O25  1  0.500  0.000  0.500  1.0
  O  O26  1  0.000  0.500  0.500  1.0
  O  O27  1  0.500  0.500  0.500  1.0
  O  O28  1  0.257  0.000  0.000  1.0
  O  O29  1  0.743  0.000  0.000  1.0
  O  O30  1  0.237  0.500  0.000  1.0
  O  O31  1  0.763  0.500  0.000  1.0
[/CIF]
.
The material described by Mg14YNbO16 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Y(1)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, edges with four equivalent Mg(3)O6 octahedra, and edges with four equivalent Mg(4)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to one O(4), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Y(1)O6 octahedra, and edges with four equivalent Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the third Mg site, Mg(3) is bonded to one O(5), one O(6), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the fourth Mg site, Mg(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Mg(4)O6 octahedra,  an edgeedge with one Y(1)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-9°. Y(1) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form YO6 octahedra that share corners with two equivalent Y(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(4)O6 octahedra, and edges with eight equivalent Mg(2)O6 octahedra. The corner-sharing octahedra are not tilted. Nb(1) is bonded to two equivalent O(6) and four equivalent O(2) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(4)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Y(1) atom to form OYMg5 octahedra that share corners with two equivalent O(2)Mg5Nb octahedra, corners with four equivalent O(1)YMg5 octahedra, edges with two equivalent O(2)Mg5Nb octahedra, edges with two equivalent O(5)Mg6 octahedra, edges with two equivalent O(4)Y2Mg4 octahedra, edges with two equivalent O(1)YMg5 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second O site, O(2) is bonded to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), and one Nb(1) atom to form OMg5Nb octahedra that share corners with two equivalent O(1)YMg5 octahedra, corners with four equivalent O(2)Mg5Nb octahedra, edges with two equivalent O(6)Mg4Nb2 octahedra, edges with two equivalent O(2)Mg5Nb octahedra, edges with two equivalent O(5)Mg6 octahedra, edges with two equivalent O(1)YMg5 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the third O site, O(3) is bonded to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms to form OMg6 octahedra that share corners with six equivalent O(3)Mg6 octahedra,  an edgeedge with one O(6)Mg4Nb2 octahedra,  an edgeedge with one O(4)Y2Mg4 octahedra, edges with two equivalent O(5)Mg6 octahedra, edges with four equivalent O(2)Mg5Nb octahedra, and edges with four equivalent O(1)YMg5 octahedra. The corner-sharing octahedral tilt angles range from 1-7°. In the fourth O site, O(4) is bonded to four equivalent Mg(2) and two equivalent Y(1) atoms to form OY2Mg4 octahedra that share corners with two equivalent O(4)Y2Mg4 octahedra, corners with four equivalent O(5)Mg6 octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with eight equivalent O(1)YMg5 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(6)Mg4Nb2 octahedra, corners with two equivalent O(5)Mg6 octahedra, corners with two equivalent O(4)Y2Mg4 octahedra, edges with four equivalent O(2)Mg5Nb octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with four equivalent O(1)YMg5 octahedra. The corner-sharing octahedra are not tilted. In the sixth O site, O(6) is bonded to four equivalent Mg(3) and two equivalent Nb(1) atoms to form OMg4Nb2 octahedra that share corners with two equivalent O(6)Mg4Nb2 octahedra, corners with four equivalent O(5)Mg6 octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with eight equivalent O(2)Mg5Nb octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_YMg14NbO16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.742
_cell_length_b   8.742
_cell_length_c   4.414
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   337.273
_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
  Y  Y0  1  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.500  0.000  0.000  1.0
  Mg  Mg2  1  0.000  0.500  0.000  1.0
  Mg  Mg3  1  0.263  0.000  0.500  1.0
  Mg  Mg4  1  0.737  0.000  0.500  1.0
  Mg  Mg5  1  0.249  0.500  0.500  1.0
  Mg  Mg6  1  0.751  0.500  0.500  1.0
  Mg  Mg7  1  0.000  0.263  0.500  1.0
  Mg  Mg8  1  0.500  0.249  0.500  1.0
  Mg  Mg9  1  0.000  0.737  0.500  1.0
  Mg  Mg10  1  0.500  0.751  0.500  1.0
  Mg  Mg11  1  0.256  0.256  0.000  1.0
  Mg  Mg12  1  0.744  0.256  0.000  1.0
  Mg  Mg13  1  0.256  0.744  0.000  1.0
  Mg  Mg14  1  0.744  0.744  0.000  1.0
  Nb  Nb15  1  0.500  0.500  0.000  1.0
  O  O16  1  0.000  0.257  0.000  1.0
  O  O17  1  0.500  0.237  0.000  1.0
  O  O18  1  0.000  0.743  0.000  1.0
  O  O19  1  0.500  0.763  0.000  1.0
  O  O20  1  0.248  0.248  0.500  1.0
  O  O21  1  0.752  0.248  0.500  1.0
  O  O22  1  0.248  0.752  0.500  1.0
  O  O23  1  0.752  0.752  0.500  1.0
  O  O24  1  0.000  0.000  0.500  1.0
  O  O25  1  0.500  0.000  0.500  1.0
  O  O26  1  0.000  0.500  0.500  1.0
  O  O27  1  0.500  0.500  0.500  1.0
  O  O28  1  0.257  0.000  0.000  1.0
  O  O29  1  0.743  0.000  0.000  1.0
  O  O30  1  0.237  0.500  0.000  1.0
  O  O31  1  0.763  0.500  0.000  1.0
[/CIF]
.