Materials Data on NaAlH4 by Materials Project

Abstract

NaAlH4 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Na1+ is bonded in a 5-coordinate geometry to five H1- atoms. There are a spread of Na–H bond distances ranging from 2.22–2.30 Å. Al3+ is bonded to six H1- atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedra tilt angles range from 11–30°. There are a spread of Al–H bond distances ranging from 1.66–1.85 Å. There are four inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted trigonal planar geometry to two equivalent Na1+ and one Al3+ atom. In the second H1- site, H1- is bonded to three equivalent Na1+ and one Al3+ atom to form corner-sharing HNa3Al tetrahedra. In the third H1- site, H1- is bonded in a linear geometry to two equivalent Al3+ atoms. In the fourth H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms.