Materials Data on Er11(AlGe4)2 by Materials Project

Abstract

Al2Er11Ge8 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are four inequivalent Er sites. In the first Er site, Er is bonded in a 4-coordinate geometry to four equivalent Al and five Ge atoms. All Er–Al bond lengths are 3.26 Å. There are four shorter (3.19 Å) and one longer (3.50 Å) Er–Ge bond lengths. In the second Er site, Er is bonded to one Al and six Ge atoms to form distorted ErAlGe6 pentagonal bipyramids that share corners with eight equivalent ErGe7 pentagonal bipyramids, an edgeedge with one ErAlGe6 pentagonal bipyramid, and faces with six ErAlGe6 pentagonal bipyramids. The Er–Al bond length is 3.13 Å. There are a spread of Er–Ge bond distances ranging from 2.76–3.38 Å. In the third Er site, Er is bonded to seven Ge atoms to form distorted ErGe7 pentagonal bipyramids that share corners with seven ErAlGe6 pentagonal bipyramids, edges with two equivalent ErGe7 pentagonal bipyramids, and faces with six ErAlGe6 pentagonal bipyramids. There are a spread of Er–Ge bond distances ranging from 2.88–3.27 Å. In the fourth Er site, Er is bonded in a 5-coordinate geometry to two equivalent Al and five Ge atoms. Both Er–Al bond lengths are 3.11 Å. There are a spread of Er–Ge bond distances ranging from 2.89–3.03 Å. Al is bonded in a 11-coordinate geometry to seven Er, two equivalent Al, and two equivalent Ge atoms. Both Al–Al bond lengths are 2.67 Å. Both Al–Ge bond lengths are 3.13 Å. There are four inequivalent Ge sites. In the first Ge site, Ge is bonded in a 8-coordinate geometry to eight Er atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to nine Er atoms. In the third Ge site, Ge is bonded in a 8-coordinate geometry to eight Er atoms. In the fourth Ge site, Ge is bonded in a 10-coordinate geometry to eight Er, one Al, and one Ge atom. The Ge–Ge bond length is 2.75 Å.