RbLi2Be2F7 crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 8-coordinate geometry to one F(3), one F(5), two equivalent F(2), two equivalent F(4), and two equivalent F(6) atoms. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one F(2), one F(4), and two equivalent F(7) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(1)F4 tetrahedra and corners with four equivalent Be(2)F4 tetrahedra. In the second Li site, Li(2) is bonded to one F(3), one F(6), and two equivalent F(1) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(2)F4 tetrahedra and corners with four equivalent Be(1)F4 tetrahedra. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one F(1), one F(3), one F(5), and one F(6) atom to form BeF4 tetrahedra that share  a cornercorner with one Be(2)F4 tetrahedra and corners with four equivalent Li(2)F4 tetrahedra. In the second Be site, Be(2) is bonded to one F(2), one F(4), one F(5), and one F(7) atom to form BeF4 tetrahedra that share  a cornercorner with one Be(1)F4 tetrahedra and corners with four equivalent Li(1)F4 tetrahedra. There are seven inequivalent F sites. In the first F site, F(7) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Be(2) atom. In the second F site, F(1) is bonded in a trigonal planar geometry to two equivalent Li(2) and one Be(1) atom. In the third F site, F(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Li(1), and one Be(2) atom. In the fourth F site, F(3) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Li(2), and one Be(1) atom. In the fifth F site, F(4) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Li(1), and one Be(2) atom. In the sixth F site, F(5) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Be(1), and one Be(2) atom. In the seventh F site, F(6) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Li(2), and one Be(1) atom.
RbLi2Be2F7 crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 8-coordinate geometry to one F(3), one F(5), two equivalent F(2), two equivalent F(4), and two equivalent F(6) atoms. The Rb(1)-F(3) bond length is 2.96 Å. The Rb(1)-F(5) bond length is 3.05 Å. There is one shorter (3.00 Å) and one longer (3.29 Å) Rb(1)-F(2) bond length. There is one shorter (3.10 Å) and one longer (3.14 Å) Rb(1)-F(4) bond length. There is one shorter (3.13 Å) and one longer (3.16 Å) Rb(1)-F(6) bond length. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one F(2), one F(4), and two equivalent F(7) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(1)F4 tetrahedra and corners with four equivalent Be(2)F4 tetrahedra. The Li(1)-F(2) bond length is 1.87 Å. The Li(1)-F(4) bond length is 1.88 Å. There is one shorter (1.89 Å) and one longer (1.91 Å) Li(1)-F(7) bond length. In the second Li site, Li(2) is bonded to one F(3), one F(6), and two equivalent F(1) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(2)F4 tetrahedra and corners with four equivalent Be(1)F4 tetrahedra. The Li(2)-F(3) bond length is 1.87 Å. The Li(2)-F(6) bond length is 1.88 Å. There is one shorter (1.90 Å) and one longer (1.91 Å) Li(2)-F(1) bond length. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one F(1), one F(3), one F(5), and one F(6) atom to form BeF4 tetrahedra that share  a cornercorner with one Be(2)F4 tetrahedra and corners with four equivalent Li(2)F4 tetrahedra. The Be(1)-F(1) bond length is 1.57 Å. The Be(1)-F(3) bond length is 1.54 Å. The Be(1)-F(5) bond length is 1.61 Å. The Be(1)-F(6) bond length is 1.55 Å. In the second Be site, Be(2) is bonded to one F(2), one F(4), one F(5), and one F(7) atom to form BeF4 tetrahedra that share  a cornercorner with one Be(1)F4 tetrahedra and corners with four equivalent Li(1)F4 tetrahedra. The Be(2)-F(2) bond length is 1.54 Å. The Be(2)-F(4) bond length is 1.55 Å. The Be(2)-F(5) bond length is 1.61 Å. The Be(2)-F(7) bond length is 1.57 Å. There are seven inequivalent F sites. In the first F site, F(7) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Be(2) atom. In the second F site, F(1) is bonded in a trigonal planar geometry to two equivalent Li(2) and one Be(1) atom. In the third F site, F(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Li(1), and one Be(2) atom. In the fourth F site, F(3) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Li(2), and one Be(1) atom. In the fifth F site, F(4) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Li(1), and one Be(2) atom. In the sixth F site, F(5) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one Be(1), and one Be(2) atom. In the seventh F site, F(6) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Li(2), and one Be(1) atom.