DOE OSTI2020
Rb3TmO3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded to four O2- atoms to form distorted RbO4 tetrahedra that share corners with five equivalent TmO4 tetrahedra and an edgeedge with one RbO4 tetrahedra. There are a spread of Rb–O bond distances ranging from 2.85–3.11 Å. In the second Rb1+ site, Rb1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Rb–O bond distances ranging from 2.84–3.50 Å. In the third Rb1+ site, Rb1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Rb–O bond distances ranging from 2.71–3.21 Å. Tm3+ is bonded to four O2- atoms to form TmO4 tetrahedra that share corners with five equivalent RbO4 tetrahedra and an edgeedge with one TmO4 tetrahedra. There are a spread of Tm–O bond distances ranging from 2.08–2.18 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to six Rb1+ and one Tm3+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Rb1+ and two equivalent Tm3+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Rb1+ and one Tm3+ atom.