Materials Data on K3TaF8 by Materials Project
K3TaF8 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of K–F bond distances ranging from 2.70–2.93 Å. Ta5+ is bonded in a distorted pentagonal bipyramidal geometry to seven F1- atoms. There is three shorter (1.97 Å) and four longer (1.99 Å) Ta–F bond length. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded to six equivalent K1+ atoms to form face-sharing FK6 octahedra. In the second F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent K1+ and one Ta5+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to three equivalent K1+ and one Ta5+ atom. In the fourth F1- site, F1- is bonded in a 4-coordinate geometry to three equivalent K1+ and one Ta5+ atom.