RbBe2B3O7 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(8), and four equivalent O(5) atoms. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(7), and two equivalent O(9) atoms. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form corner-sharing BeO4 tetrahedra. In the second Be site, Be(2) is bonded to one O(3), one O(9), and two equivalent O(4) atoms to form corner-sharing BeO4 tetrahedra. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(2) atoms. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(4) atoms. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(5), one O(6), and one O(7) atom. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(7), one O(8), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(2) and one B(2) atom. In the second O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Be(1), and one B(3) atom. In the third O site, O(6) is bonded in a bent 120 degrees geometry to two equivalent B(3) atoms. In the fourth O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Rb(2), one B(3), and one B(4) atom. In the fifth O site, O(8) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1) and two equivalent B(4) atoms. In the sixth O site, O(9) is bonded in a bent 150 degrees geometry to one Rb(2), one Be(2), and one B(4) atom. In the seventh O site, O(1) is bonded in a trigonal planar geometry to one Rb(1), two equivalent Be(1), and one B(1) atom. In the eighth O site, O(2) is bonded in a trigonal planar geometry to two equivalent Be(1) and one B(1) atom. In the ninth O site, O(3) is bonded in a distorted trigonal planar geometry to one Rb(2), two equivalent Be(2), and one B(2) atom.
RbBe2B3O7 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(8), and four equivalent O(5) atoms. The Rb(1)-O(1) bond length is 3.15 Å. There is one shorter (3.22 Å) and one longer (3.28 Å) Rb(1)-O(8) bond length. There are two shorter (2.84 Å) and two longer (3.02 Å) Rb(1)-O(5) bond lengths. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(7), and two equivalent O(9) atoms. The Rb(2)-O(3) bond length is 3.08 Å. Both Rb(2)-O(7) bond lengths are 2.97 Å. Both Rb(2)-O(9) bond lengths are 3.01 Å. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form corner-sharing BeO4 tetrahedra. The Be(1)-O(1) bond length is 1.69 Å. The Be(1)-O(5) bond length is 1.62 Å. There is one shorter (1.65 Å) and one longer (1.68 Å) Be(1)-O(2) bond length. In the second Be site, Be(2) is bonded to one O(3), one O(9), and two equivalent O(4) atoms to form corner-sharing BeO4 tetrahedra. The Be(2)-O(3) bond length is 1.66 Å. The Be(2)-O(9) bond length is 1.58 Å. There is one shorter (1.65 Å) and one longer (1.67 Å) Be(2)-O(4) bond length. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(2) atoms. The B(1)-O(1) bond length is 1.39 Å. Both B(1)-O(2) bond lengths are 1.39 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(4) atoms. The B(2)-O(3) bond length is 1.38 Å. Both B(2)-O(4) bond lengths are 1.38 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(5), one O(6), and one O(7) atom. The B(3)-O(5) bond length is 1.34 Å. The B(3)-O(6) bond length is 1.40 Å. The B(3)-O(7) bond length is 1.40 Å. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(7), one O(8), and one O(9) atom. The B(4)-O(7) bond length is 1.40 Å. The B(4)-O(8) bond length is 1.40 Å. The B(4)-O(9) bond length is 1.33 Å. There are nine inequivalent O sites. In the first O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(2) and one B(2) atom. In the second O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one Be(1), and one B(3) atom. In the third O site, O(6) is bonded in a bent 120 degrees geometry to two equivalent B(3) atoms. In the fourth O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Rb(2), one B(3), and one B(4) atom. In the fifth O site, O(8) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1) and two equivalent B(4) atoms. In the sixth O site, O(9) is bonded in a bent 150 degrees geometry to one Rb(2), one Be(2), and one B(4) atom. In the seventh O site, O(1) is bonded in a trigonal planar geometry to one Rb(1), two equivalent Be(1), and one B(1) atom. In the eighth O site, O(2) is bonded in a trigonal planar geometry to two equivalent Be(1) and one B(1) atom. In the ninth O site, O(3) is bonded in a distorted trigonal planar geometry to one Rb(2), two equivalent Be(2), and one B(2) atom.