Materials Data on ThNb4O12 by Materials Project
ThNb4O12 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Th4+ is bonded to twelve O2- atoms to form ThO12 cuboctahedra that share corners with four equivalent ThO12 cuboctahedra and faces with eight equivalent NbO6 octahedra. There are eight shorter (2.59 Å) and four longer (2.81 Å) Th–O bond lengths. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six equivalent NbO6 octahedra and faces with two equivalent ThO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–16°. There are a spread of Nb–O bond distances ranging from 1.95–2.04 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Th4+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to two equivalent Th4+ and two equivalent Nb5+ atoms.