Materials Data on NaTmGeO4 by Materials Project
NaTmGeO4 is Hausmannite-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with four equivalent TmO6 octahedra, corners with two equivalent GeO4 tetrahedra, edges with two equivalent NaO6 octahedra, edges with two equivalent TmO6 octahedra, and edges with two equivalent GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–66°. There are a spread of Na–O bond distances ranging from 2.37–2.55 Å. Tm3+ is bonded to six O2- atoms to form TmO6 octahedra that share corners with four equivalent NaO6 octahedra, corners with four equivalent TmO6 octahedra, corners with four equivalent GeO4 tetrahedra, edges with two equivalent NaO6 octahedra, and an edgeedge with one GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–66°. There are a spread of Tm–O bond distances ranging from 2.19–2.33 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with four equivalent TmO6 octahedra, an edgeedge with one TmO6 octahedra, and edges with two equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 44–63°. There are a spread of Ge–O bond distances ranging from 1.75–1.81 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+, one Tm3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+, two equivalent Tm3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Tm3+, and one Ge4+ atom.