Materials Data on BaAl2O4 by Materials Project

Abstract

BaAl2O4 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.83–3.21 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is one shorter (1.76 Å) and three longer (1.77 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is one shorter (1.76 Å) and three longer (1.77 Å) Al–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three equivalent Ba2+ and two Al3+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Al3+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Ba2+ and two equivalent Al3+ atoms.