NaGdTiNbO6F crystallizes in the tetragonal P4_322 space group. Na(1) is bonded to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms to form distorted NaO6F2 hexagonal bipyramids that share edges with two equivalent Na(1)O6F2 hexagonal bipyramids, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. Gd(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent F(1) atoms. Ti(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Na(1)O6F2 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-47°. Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, and edges with four equivalent Na(1)O6F2 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-47°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1) and two equivalent Nb(1) atoms to form distorted ONa2Nb2 trigonal pyramids that share corners with two equivalent F(1)Na2Gd2 tetrahedra,  an edgeedge with one F(1)Na2Gd2 tetrahedra, and edges with two equivalent O(1)Na2Nb2 trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Gd(1), one Ti(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Gd(1), one Ti(1), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Gd(1) and two equivalent Ti(1) atoms. F(1) is bonded to two equivalent Na(1) and two equivalent Gd(1) atoms to form FNa2Gd2 tetrahedra that share corners with four equivalent F(1)Na2Gd2 tetrahedra, corners with two equivalent O(1)Na2Nb2 trigonal pyramids, and  an edgeedge with one O(1)Na2Nb2 trigonal pyramid.
NaGdTiNbO6F crystallizes in the tetragonal P4_322 space group. Na(1) is bonded to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms to form distorted NaO6F2 hexagonal bipyramids that share edges with two equivalent Na(1)O6F2 hexagonal bipyramids, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. Both Na(1)-O(1) bond lengths are 2.57 Å. Both Na(1)-O(2) bond lengths are 2.74 Å. Both Na(1)-O(3) bond lengths are 2.74 Å. Both Na(1)-F(1) bond lengths are 2.24 Å. Gd(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent F(1) atoms. Both Gd(1)-O(2) bond lengths are 2.47 Å. Both Gd(1)-O(3) bond lengths are 2.35 Å. Both Gd(1)-O(4) bond lengths are 2.77 Å. Both Gd(1)-F(1) bond lengths are 2.28 Å. Ti(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Na(1)O6F2 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-47°. Both Ti(1)-O(2) bond lengths are 1.99 Å. Both Ti(1)-O(3) bond lengths are 2.02 Å. Both Ti(1)-O(4) bond lengths are 1.93 Å. Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, and edges with four equivalent Na(1)O6F2 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-47°. Both Nb(1)-O(1) bond lengths are 2.00 Å. Both Nb(1)-O(2) bond lengths are 2.00 Å. Both Nb(1)-O(3) bond lengths are 2.02 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1) and two equivalent Nb(1) atoms to form distorted ONa2Nb2 trigonal pyramids that share corners with two equivalent F(1)Na2Gd2 tetrahedra,  an edgeedge with one F(1)Na2Gd2 tetrahedra, and edges with two equivalent O(1)Na2Nb2 trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Gd(1), one Ti(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Gd(1), one Ti(1), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Gd(1) and two equivalent Ti(1) atoms. F(1) is bonded to two equivalent Na(1) and two equivalent Gd(1) atoms to form FNa2Gd2 tetrahedra that share corners with four equivalent F(1)Na2Gd2 tetrahedra, corners with two equivalent O(1)Na2Nb2 trigonal pyramids, and  an edgeedge with one O(1)Na2Nb2 trigonal pyramid.