Materials Data on Na3AlH6 by Materials Project

Abstract

Na3AlH6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six H1- atoms to form NaH6 octahedra that share corners with six equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 31–37°. There are a spread of Na–H bond distances ranging from 2.23–2.28 Å. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to seven H1- atoms. There are a spread of Na–H bond distances ranging from 2.27–2.66 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with six equivalent NaH6 octahedra. The corner-sharing octahedra tilt angles range from 31–37°. There are a spread of Al–H bond distances ranging from 1.76–1.78 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a 4-coordinate geometry to three Na1+ and one Al3+ atom. In the second H1- site, H1- is bonded in a 3-coordinate geometry to four Na1+ and one Al3+ atom. In the third H1- site, H1- is bonded to three Na1+ and one Al3+ atom to form distorted corner-sharing HNa3Al tetrahedra.