Materials Data on Tm2AlGe3 by Materials Project

Abstract

Tm2AlGe3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded in a 7-coordinate geometry to two equivalent Al and nine Ge atoms. Both Tm–Al bond lengths are 3.29 Å. There are a spread of Tm–Ge bond distances ranging from 2.95–3.31 Å. In the second Tm site, Tm is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of Tm–Ge bond distances ranging from 2.91–3.02 Å. Al is bonded to two equivalent Tm and four Ge atoms to form distorted AlTm2Ge4 tetrahedra that share corners with two equivalent GeTm4Al3 pentagonal bipyramids and edges with four equivalent AlTm2Ge4 tetrahedra. There are a spread of Al–Ge bond distances ranging from 2.54–2.69 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded to four Tm and three equivalent Al atoms to form distorted GeTm4Al3 pentagonal bipyramids that share corners with two equivalent AlTm2Ge4 tetrahedra and edges with six equivalent GeTm4Al3 pentagonal bipyramids. In the second Ge site, Ge is bonded in a 4-coordinate geometry to six Tm and two equivalent Ge atoms. There are one shorter (2.56 Å) and one longer (2.67 Å) Ge–Ge bond lengths. In the third Ge site, Ge is bonded in a 9-coordinate geometry to six Tm, one Al, and two equivalent Ge atoms.