Materials Data on Na3TaF8 by Materials Project

Na3TaF8 is Esseneite-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Na–F bond distances ranging from 2.31–2.67 Å. In the second Na1+ site, Na1+ is bonded in a distorted octahedral geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.27–2.48 Å. Ta5+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Ta–F bond distances ranging from 2.01–2.07 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded to three Na1+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing FNa3Ta tetrahedra. In the second F1- site, F1- is bonded in a 2-coordinate geometry to two equivalent Na1+ and one Ta5+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to three Na1+ and one Ta5+ atom. In the fourth F1- site, F1- is bonded to three Na1+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing FNa3Ta tetrahedra.