Materials Data on Ho2AlGe3 by Materials Project

Abstract

Ho2AlGe3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 7-coordinate geometry to two equivalent Al and nine Ge atoms. Both Ho–Al bond lengths are 3.32 Å. There are a spread of Ho–Ge bond distances ranging from 2.97–3.33 Å. In the second Ho site, Ho is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of Ho–Ge bond distances ranging from 2.94–3.05 Å. Al is bonded to two equivalent Ho and four Ge atoms to form distorted AlHo2Ge4 tetrahedra that share corners with two equivalent GeHo4Al3 pentagonal bipyramids and edges with four equivalent AlHo2Ge4 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 Ho and three equivalent Al atoms to form distorted GeHo4Al3 pentagonal bipyramids that share corners with two equivalent AlHo2Ge4 tetrahedra and edges with six equivalent GeHo4Al3 pentagonal bipyramids. In the second Ge site, Ge is bonded in a 4-coordinate geometry to six Ho and two equivalent Ge atoms. There are one shorter (2.58 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 Ho, one Al, and two equivalent Ge atoms.