Materials Data on BaAl2O4 by Materials Project
BaAl2O4 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.70–3.27 Å. In the second Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.81–3.05 Å. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is three shorter (1.77 Å) and one longer (1.78 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 three shorter (1.76 Å) and one longer (1.78 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is two shorter (1.77 Å) and two longer (1.78 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.76–1.78 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two 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 Al3+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Al3+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Al3+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to three equivalent Ba2+ and two Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ba2+ and two Al3+ atoms.