Materials Data on NaHf4(NCl)4 by Materials Project
NaHf4(NCl)4 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. Na is bonded to six Cl atoms to form edge-sharing NaCl6 octahedra. There are four shorter (2.76 Å) and two longer (2.80 Å) Na–Cl bond lengths. There are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 4-coordinate geometry to four N and three Cl atoms. There are one shorter (2.13 Å) and three longer (2.14 Å) Hf–N bond lengths. There are two shorter (2.86 Å) and one longer (2.92 Å) Hf–Cl bond lengths. In the second Hf site, Hf is bonded in a 4-coordinate geometry to four N and three Cl atoms. There are a spread of Hf–N bond distances ranging from 2.11–2.13 Å. There are one shorter (2.86 Å) and two longer (2.94 Å) Hf–Cl bond lengths. There are two inequivalent N sites. In the first N site, N is bonded to four Hf atoms to form NHf4 trigonal pyramids that share corners with four equivalent ClNa2Hf3 square pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one ClNa2Hf3 square pyramid, and edges with three NHf4 trigonal pyramids. In the second N site, N is bonded to four Hf atoms to form NHf4 trigonal pyramids that share corners with two equivalent ClNa2Hf3 square pyramids, corners with six NHf4 trigonal pyramids, edges with two equivalent ClNa2Hf3 square pyramids, and edges with three NHf4 trigonal pyramids. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a distorted see-saw-like geometry to one Na and three Hf atoms. In the second Cl site, Cl is bonded to two equivalent Na and three Hf atoms to form distorted ClNa2Hf3 square pyramids that share corners with two equivalent ClNa2Hf3 square pyramids, corners with six NHf4 trigonal pyramids, edges with three equivalent ClNa2Hf3 square pyramids, and edges with three NHf4 trigonal pyramids.