Materials Data on Tb2Th2O5 by Materials Project

Th2Tb2O5 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Th is bonded in a distorted pentagonal planar geometry to four equivalent Tb and five O atoms. All Th–Tb bond lengths are 4.32 Å. There are four shorter (2.23 Å) and one longer (2.24 Å) Th–O bond lengths. There are two inequivalent Tb sites. In the first Tb site, Tb is bonded to eight equivalent Th and four equivalent Tb atoms to form TbTb4Th8 cuboctahedra that share corners with four equivalent TbTb4Th8 cuboctahedra, corners with sixteen equivalent OTb2Th2 tetrahedra, edges with eight equivalent OTb2Th2 tetrahedra, and faces with eight equivalent TbTb4Th8 cuboctahedra. All Tb–Tb bond lengths are 4.26 Å. In the second Tb site, Tb is bonded in a distorted body-centered cubic geometry to eight equivalent O atoms. All Tb–O bond lengths are 2.65 Å. There are two inequivalent O sites. In the first O site, O is bonded to two equivalent Th and two equivalent Tb atoms to form distorted OTb2Th2 tetrahedra that share corners with four equivalent TbTb4Th8 cuboctahedra, corners with ten equivalent OTb2Th2 tetrahedra, edges with two equivalent TbTb4Th8 cuboctahedra, and edges with five equivalent OTb2Th2 tetrahedra. In the second O site, O is bonded in a linear geometry to two equivalent Th atoms.