Materials Data on Na2HF4 by Materials Project
Na2HF4 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded to six F atoms to form distorted edge-sharing NaF6 octahedra. There are four shorter (2.32 Å) and two longer (2.39 Å) Na–F bond lengths. In the second Na site, Na is bonded to six F atoms to form edge-sharing NaF6 octahedra. There are two shorter (2.29 Å) and four longer (2.37 Å) Na–F bond lengths. H is bonded in a linear geometry to two equivalent F atoms. Both H–F bond lengths are 1.14 Å. There are two inequivalent F sites. In the first F site, F is bonded in a distorted trigonal non-coplanar geometry to three Na atoms. In the second F site, F is bonded to three Na and one H atom to form a mixture of distorted corner and edge-sharing FNa3H tetrahedra.