Materials Data on NaAlI4 by Materials Project
NaAlI4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to six I1- atoms to form distorted NaI6 pentagonal pyramids that share corners with four equivalent NaI6 pentagonal pyramids, corners with two equivalent AlI4 tetrahedra, and edges with two equivalent AlI4 tetrahedra. There are a spread of Na–I bond distances ranging from 3.21–3.47 Å. Al3+ is bonded to four I1- atoms to form AlI4 tetrahedra that share corners with two equivalent NaI6 pentagonal pyramids and edges with two equivalent NaI6 pentagonal pyramids. There are a spread of Al–I bond distances ranging from 2.55–2.58 Å. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in an L-shaped geometry to one Na1+ and one Al3+ atom. In the second I1- site, I1- is bonded in an L-shaped geometry to one Na1+ and one Al3+ atom. In the third I1- site, I1- is bonded in a distorted T-shaped geometry to two equivalent Na1+ and one Al3+ atom.