Materials Data on La2Al4O9 by Materials Project
La2Al4O9 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. La3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.30–2.57 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent AlO4 tetrahedra and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.02 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–55°. There are a spread of Al–O bond distances ranging from 1.75–1.79 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ and two Al3+ atoms. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to three Al3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ and two equivalent Al3+ atoms.