Materials Data on Na3GdI6 by Materials Project

Na3GdI6 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six I1- atoms to form NaI6 octahedra that share corners with two equivalent NaI6 octahedra, edges with three equivalent GdI6 octahedra, and edges with five NaI6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Na–I bond distances ranging from 3.23–3.26 Å. In the second Na1+ site, Na1+ is bonded to six I1- atoms to form NaI6 octahedra that share corners with two equivalent GdI6 octahedra, corners with four NaI6 octahedra, edges with two equivalent GdI6 octahedra, and edges with four NaI6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Na–I bond distances ranging from 3.20–3.29 Å. In the third Na1+ site, Na1+ is bonded to six I1- atoms to form NaI6 octahedra that share corners with two equivalent NaI6 octahedra, edges with three equivalent GdI6 octahedra, and edges with five NaI6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are four shorter (3.24 Å) and two longer (3.25 Å) Na–I bond lengths. Gd3+ is bonded to six I1- atoms to form GdI6 octahedra that share corners with two equivalent NaI6 octahedra and edges with eight NaI6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (3.07 Å) and four longer (3.10 Å) Gd–I bond lengths. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a rectangular see-saw-like geometry to three Na1+ and one Gd3+ atom. In the second I1- site, I1- is bonded in a rectangular see-saw-like geometry to three Na1+ and one Gd3+ atom. In the third I1- site, I1- is bonded in a rectangular see-saw-like geometry to three Na1+ and one Gd3+ atom.