Rb2NaAl6F21 crystallizes in the monoclinic C2 space group. Rb(1) is bonded in a 12-coordinate geometry to one F(11), one F(2), one F(3), one F(5), one F(7), one F(8), two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms. Na(1) is bonded to two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms to form NaF6 octahedra that share corners with two equivalent Al(1)F6 octahedra, corners with two equivalent Al(2)F6 octahedra, and corners with two equivalent Al(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one F(11), one F(3), one F(4), one F(6), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-63°. In the second Al site, Al(2) is bonded to one F(10), one F(2), one F(4), one F(5), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-56°. In the third Al site, Al(3) is bonded to one F(1), one F(11), one F(2), one F(3), one F(5), and one F(9) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra,  a cornercorner with one Al(3)F6 octahedra, corners with two equivalent Al(1)F6 octahedra, and corners with two equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 14-60°. There are eleven inequivalent F sites. In the first F site, F(1) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(3) atom. In the second F site, F(2) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the third F site, F(3) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom. In the fourth F site, F(4) is bonded in a linear geometry to one Al(1) and one Al(2) atom. In the fifth F site, F(5) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the sixth F site, F(6) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(1) atom. In the seventh F site, F(7) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the eighth F site, F(8) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the ninth F site, F(9) is bonded in a linear geometry to two equivalent Al(3) atoms. In the tenth F site, F(10) is bonded in a 3-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(2) atom. In the eleventh F site, F(11) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom.
Rb2NaAl6F21 crystallizes in the monoclinic C2 space group. Rb(1) is bonded in a 12-coordinate geometry to one F(11), one F(2), one F(3), one F(5), one F(7), one F(8), two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms. The Rb(1)-F(11) bond length is 3.33 Å. The Rb(1)-F(2) bond length is 3.33 Å. The Rb(1)-F(3) bond length is 3.31 Å. The Rb(1)-F(5) bond length is 3.33 Å. The Rb(1)-F(7) bond length is 3.30 Å. The Rb(1)-F(8) bond length is 3.31 Å. There is one shorter (2.96 Å) and one longer (3.15 Å) Rb(1)-F(1) bond length. There is one shorter (2.90 Å) and one longer (3.39 Å) Rb(1)-F(10) bond length. There is one shorter (2.96 Å) and one longer (3.37 Å) Rb(1)-F(6) bond length. Na(1) is bonded to two equivalent F(1), two equivalent F(10), and two equivalent F(6) atoms to form NaF6 octahedra that share corners with two equivalent Al(1)F6 octahedra, corners with two equivalent Al(2)F6 octahedra, and corners with two equivalent Al(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. Both Na(1)-F(1) bond lengths are 2.36 Å. Both Na(1)-F(10) bond lengths are 2.32 Å. Both Na(1)-F(6) bond lengths are 2.37 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one F(11), one F(3), one F(4), one F(6), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-63°. The Al(1)-F(11) bond length is 1.85 Å. The Al(1)-F(3) bond length is 1.84 Å. The Al(1)-F(4) bond length is 1.83 Å. The Al(1)-F(6) bond length is 1.77 Å. The Al(1)-F(7) bond length is 1.84 Å. The Al(1)-F(8) bond length is 1.84 Å. In the second Al site, Al(2) is bonded to one F(10), one F(2), one F(4), one F(5), one F(7), and one F(8) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra, corners with two equivalent Al(3)F6 octahedra, and corners with three equivalent Al(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 11-56°. The Al(2)-F(10) bond length is 1.76 Å. The Al(2)-F(2) bond length is 1.84 Å. The Al(2)-F(4) bond length is 1.82 Å. The Al(2)-F(5) bond length is 1.85 Å. The Al(2)-F(7) bond length is 1.85 Å. The Al(2)-F(8) bond length is 1.84 Å. In the third Al site, Al(3) is bonded to one F(1), one F(11), one F(2), one F(3), one F(5), and one F(9) atom to form AlF6 octahedra that share  a cornercorner with one Na(1)F6 octahedra,  a cornercorner with one Al(3)F6 octahedra, corners with two equivalent Al(1)F6 octahedra, and corners with two equivalent Al(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 14-60°. The Al(3)-F(1) bond length is 1.77 Å. The Al(3)-F(11) bond length is 1.85 Å. The Al(3)-F(2) bond length is 1.84 Å. The Al(3)-F(3) bond length is 1.84 Å. The Al(3)-F(5) bond length is 1.84 Å. The Al(3)-F(9) bond length is 1.83 Å. There are eleven inequivalent F sites. In the first F site, F(1) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(3) atom. In the second F site, F(2) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the third F site, F(3) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom. In the fourth F site, F(4) is bonded in a linear geometry to one Al(1) and one Al(2) atom. In the fifth F site, F(5) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(2), and one Al(3) atom. In the sixth F site, F(6) is bonded in a 1-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(1) atom. In the seventh F site, F(7) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the eighth F site, F(8) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(2) atom. In the ninth F site, F(9) is bonded in a linear geometry to two equivalent Al(3) atoms. In the tenth F site, F(10) is bonded in a 3-coordinate geometry to two equivalent Rb(1), one Na(1), and one Al(2) atom. In the eleventh F site, F(11) is bonded in a bent 150 degrees geometry to one Rb(1), one Al(1), and one Al(3) atom.