Materials Data on Lu4Al2O9 by Materials Project

Abstract

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 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 2.15–2.32 Å. In the second Lu3+ site, Lu3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Lu–O bond distances ranging from 2.18–2.33 Å. In the third 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 2.21–2.59 Å. In the fourth 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 2.22–2.48 Å. There are two inequivalent Al3+ sites. In the first 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 40–54°. There is three shorter (1.76 Å) and one longer (1.77 Å) Al–O bond length. In the second 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 53–62°. There are a spread of Al–O bond distances ranging from 1.74–1.77 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 to four Lu3+ atoms to form OLu4 tetrahedra that share corners with six OLu2Al2 tetrahedra and edges with three OLu4 tetrahedra. In the third O2- site, O2- is bonded to two Lu3+ and two Al3+ atoms to form a mixture of distorted edge and corner-sharing OLu2Al2 tetrahedra. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Lu3+ and one Al3+ atom. In the fifth O2- site, O2- is bonded to four Lu3+ atoms to form a mixture of edge and corner-sharing OLu4 tetrahedra. In the sixth O2- site, O2- is bonded to three Lu3+ and one Al3+ atom to form distorted OLu3Al tetrahedra that share corners with six OLu4 tetrahedra and an edgeedge with one OLu2Al2 tetrahedra. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Lu3+ and one Al3+ atom. In the eighth O2- site, O2- is bonded in a trigonal planar geometry to two Lu3+ and one Al3+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Lu3+ and one Al3+ atom.