Materials Data on Er2AlGe3 by Materials Project
Er2AlGe3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Er sites. In the first Er site, Er is bonded in a 7-coordinate geometry to two equivalent Al and nine Ge atoms. Both Er–Al bond lengths are 3.31 Å. There are a spread of Er–Ge bond distances ranging from 2.96–3.33 Å. In the second Er site, Er is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of Er–Ge bond distances ranging from 2.93–3.04 Å. Al is bonded to two equivalent Er and four Ge atoms to form distorted AlEr2Ge4 tetrahedra that share corners with two equivalent GeEr4Al3 pentagonal bipyramids and edges with four equivalent AlEr2Ge4 tetrahedra. There are a spread of Al–Ge bond distances ranging from 2.55–2.70 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded to four Er and three equivalent Al atoms to form distorted GeEr4Al3 pentagonal bipyramids that share corners with two equivalent AlEr2Ge4 tetrahedra and edges with six equivalent GeEr4Al3 pentagonal bipyramids. In the second Ge site, Ge is bonded in a 4-coordinate geometry to six Er and two equivalent Ge atoms. There are one shorter (2.57 Å) and one longer (2.68 Å) Ge–Ge bond lengths. In the third Ge site, Ge is bonded in a 9-coordinate geometry to six Er, one Al, and two equivalent Ge atoms.