Na3GdBr6 is Ilmenite-like structured and crystallizes in the trigonal R3 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form NaBr6 octahedra that share corners with three equivalent Na(2)Br6 octahedra, corners with six equivalent Na(3)Br6 octahedra, edges with three equivalent Gd(1)Br6 octahedra, and  a faceface with one Na(2)Br6 octahedra. The corner-sharing octahedral tilt angles range from 47-60°. In the second Na site, Na(2) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form NaBr6 octahedra that share corners with three equivalent Na(1)Br6 octahedra, corners with six equivalent Gd(1)Br6 octahedra, edges with three equivalent Na(3)Br6 octahedra, and  a faceface with one Na(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 42-60°. In the third Na site, Na(3) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form distorted NaBr6 octahedra that share corners with three equivalent Gd(1)Br6 octahedra, corners with six equivalent Na(1)Br6 octahedra, edges with three equivalent Na(2)Br6 octahedra, and  a faceface with one Gd(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. Gd(1) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form GdBr6 octahedra that share corners with three equivalent Na(3)Br6 octahedra, corners with six equivalent Na(2)Br6 octahedra, edges with three equivalent Na(1)Br6 octahedra, and  a faceface with one Na(3)Br6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one Na(3), and one Gd(1) atom. In the second Br site, Br(2) is bonded to one Na(1), one Na(2), one Na(3), and one Gd(1) atom to form a mixture of distorted corner and edge-sharing BrNa3Gd trigonal pyramids.
Na3GdBr6 is Ilmenite-like structured and crystallizes in the trigonal R3 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form NaBr6 octahedra that share corners with three equivalent Na(2)Br6 octahedra, corners with six equivalent Na(3)Br6 octahedra, edges with three equivalent Gd(1)Br6 octahedra, and  a faceface with one Na(2)Br6 octahedra. The corner-sharing octahedral tilt angles range from 47-60°. All Na(1)-Br(1) bond lengths are 3.01 Å. All Na(1)-Br(2) bond lengths are 2.91 Å. In the second Na site, Na(2) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form NaBr6 octahedra that share corners with three equivalent Na(1)Br6 octahedra, corners with six equivalent Gd(1)Br6 octahedra, edges with three equivalent Na(3)Br6 octahedra, and  a faceface with one Na(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 42-60°. All Na(2)-Br(1) bond lengths are 3.03 Å. All Na(2)-Br(2) bond lengths are 2.92 Å. In the third Na site, Na(3) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form distorted NaBr6 octahedra that share corners with three equivalent Gd(1)Br6 octahedra, corners with six equivalent Na(1)Br6 octahedra, edges with three equivalent Na(2)Br6 octahedra, and  a faceface with one Gd(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. All Na(3)-Br(1) bond lengths are 2.93 Å. All Na(3)-Br(2) bond lengths are 3.05 Å. Gd(1) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form GdBr6 octahedra that share corners with three equivalent Na(3)Br6 octahedra, corners with six equivalent Na(2)Br6 octahedra, edges with three equivalent Na(1)Br6 octahedra, and  a faceface with one Na(3)Br6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. All Gd(1)-Br(1) bond lengths are 2.82 Å. All Gd(1)-Br(2) bond lengths are 2.85 Å. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one Na(3), and one Gd(1) atom. In the second Br site, Br(2) is bonded to one Na(1), one Na(2), one Na(3), and one Gd(1) atom to form a mixture of distorted corner and edge-sharing BrNa3Gd trigonal pyramids.