Materials Data on RbNb(GeO3)3 by Materials Project
RbNb(GeO3)3 crystallizes in the hexagonal P-6c2 space group. The structure is three-dimensional. Rb1+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Rb–O bond lengths are 3.04 Å. Nb5+ is bonded to six equivalent O2- atoms to form NbO6 octahedra that share corners with six equivalent GeO4 tetrahedra. All Nb–O bond lengths are 2.01 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent NbO6 octahedra and corners with two equivalent GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There is two shorter (1.75 Å) and two longer (1.78 Å) Ge–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Ge4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Nb5+, and one Ge4+ atom.