Materials Data on Rb2NaAl6F21 by Materials Project
Rb2NaAl6F21 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Rb1+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Rb–F bond distances ranging from 2.90–3.39 Å. Na1+ is bonded to six F1- atoms to form NaF6 octahedra that share corners with six AlF6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Na–F bond distances ranging from 2.32–2.37 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share a cornercorner with one NaF6 octahedra and corners with five AlF6 octahedra. The corner-sharing octahedra tilt angles range from 11–63°. There are a spread of Al–F bond distances ranging from 1.77–1.85 Å. In the second Al3+ site, Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share a cornercorner with one NaF6 octahedra and corners with five AlF6 octahedra. The corner-sharing octahedra tilt angles range from 11–56°. There are a spread of Al–F bond distances ranging from 1.76–1.85 Å. In the third Al3+ site, Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share a cornercorner with one NaF6 octahedra and corners with five AlF6 octahedra. The corner-sharing octahedra tilt angles range from 14–60°. There are a spread of Al–F bond distances ranging from 1.77–1.85 Å. There are eleven inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent Rb1+, one Na1+, and one Al3+ atom. In the second F1- site, F1- is bonded in a bent 150 degrees geometry to one Rb1+ and two Al3+ atoms. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to one Rb1+ and two Al3+ atoms. In the fourth F1- site, F1- is bonded in a linear geometry to two Al3+ atoms. In the fifth F1- site, F1- is bonded in a bent 150 degrees geometry to one Rb1+ and two Al3+ atoms. In the sixth F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent Rb1+, one Na1+, and one Al3+ atom. In the seventh F1- site, F1- is bonded in a bent 150 degrees geometry to one Rb1+ and two Al3+ atoms. In the eighth F1- site, F1- is bonded in a bent 150 degrees geometry to one Rb1+ and two Al3+ atoms. In the ninth F1- site, F1- is bonded in a linear geometry to two equivalent Al3+ atoms. In the tenth F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent Rb1+, one Na1+, and one Al3+ atom. In the eleventh F1- site, F1- is bonded in a bent 150 degrees geometry to one Rb1+ and two Al3+ atoms.