DOE OSTI2020
(Rb6O)2Rb4O crystallizes in the orthorhombic F222 space group. The structure is three-dimensional and consists of eight Rb4O clusters and one Rb6O framework. In each Rb4O cluster, there are two inequivalent Rb sites. In the first Rb site, Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.63 Å. In the second Rb site, Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.64 Å. O is bonded in a rectangular see-saw-like geometry to four Rb atoms. In the Rb6O framework, there are nine inequivalent Rb sites. In the first Rb site, Rb is bonded in a distorted square co-planar geometry to four equivalent Rb atoms. All Rb–Rb bond lengths are 4.90 Å. In the second Rb site, Rb is bonded in a 4-coordinate geometry to eight Rb atoms. There are four shorter (4.94 Å) and four longer (5.12 Å) Rb–Rb bond lengths. In the third Rb site, Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.82 Å. In the fourth Rb site, Rb is bonded in a single-bond geometry to one Rb and one O atom. The Rb–O bond length is 2.89 Å. In the fifth Rb site, Rb is bonded in a single-bond geometry to one Rb and one O atom. The Rb–O bond length is 2.76 Å. In the sixth Rb site, Rb is bonded in a single-bond geometry to one Rb and one O atom. The Rb–O bond length is 2.68 Å. In the seventh Rb site, Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.77 Å. In the eighth Rb site, Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.84 Å. In the ninth Rb site, Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.63 Å. There are two inequivalent O sites. In the first O site, O is bonded in an octahedral geometry to six Rb atoms. In the second O site, O is bonded in a trigonal bipyramidal geometry to five Rb atoms.