DOI: 10.17188/1307006
title: Materials Data on Lu4Al2O9 by Materials Project

description: Lu4Al2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Lu3+ sites. In the first Lu3+ site, Lu3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Lu–O bond distances ranging from 2.22–2.59 Å. In the second Lu3+ site, Lu3+ is bonded to six O2- atoms to form LuO6 octahedra that share corners with three equivalent AlO4 tetrahedra, corners with two equivalent AlO4 trigonal pyramids, and edges with two equivalent LuO7 pentagonal bipyramids. There are a spread of Lu–O bond distances ranging from 2.14–2.32 Å. In the third Lu3+ site, Lu3+ is bonded to seven O2- atoms to form distorted LuO7 pentagonal bipyramids that share a cornercorner with one AlO4 tetrahedra, corners with two equivalent AlO4 trigonal pyramids, edges with two equivalent LuO6 octahedra, an edgeedge with one AlO4 tetrahedra, and an edgeedge with one AlO4 trigonal pyramid. There are a spread of Lu–O bond distances ranging from 2.19–2.45 Å. In the fourth Lu3+ site, Lu3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Lu–O bond distances ranging from 2.19–2.72 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent LuO6 octahedra, a cornercorner with one LuO7 pentagonal bipyramid, a cornercorner with one AlO4 trigonal pyramid, and an edgeedge with one LuO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 54–66°. There are a spread of Al–O bond distances ranging from 1.75–1.78 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 trigonal pyramids that share corners with two equivalent LuO6 octahedra, corners with two equivalent LuO7 pentagonal bipyramids, a cornercorner with one AlO4 tetrahedra, and an edgeedge with one LuO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 43–65°. There are a spread of Al–O bond distances ranging from 1.75–1.77 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Lu3+ and one Al3+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Lu3+ and one Al3+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Lu3+ and one Al3+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Lu3+ and one Al3+ atom. In the fifth O2- site, O2- is bonded to three Lu3+ and one Al3+ atom to form distorted corner-sharing OLu3Al tetrahedra. In the sixth O2- site, O2- is bonded to four Lu3+ atoms to form OLu4 tetrahedra that share corners with five OLu3Al tetrahedra and edges with two OLu4 tetrahedra. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Lu3+ and two Al3+ atoms. In the eighth O2- site, O2- is bonded to four Lu3+ atoms to form OLu4 tetrahedra that share corners with four OLu3Al tetrahedra and edges with two OLu4 tetrahedra. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to three Lu3+ and one Al3+ atom.