Preparation and rietveld refinement of the structure of β-Li3AlF6

The β-modification of Li3AlF6 has been prepared by heating an appropriate mixture of LiF and AlF3 at 820 °C under argon atmosphere and subsequently slow cooling it to room temperature. β-Li3AlF6 is isotypic to β-Li3VF6 and crystallizes inC2/c witha = 14.201(1)Å, b = 8.387(1)Å, c = 9.860(1)Å, and β = 94.07(1) °. The structural parameters have been refined by Rietveld analysis from powder data. A comparison of the structures of β-Li3AlF6 and β-Li3TiF6 is made for the analysis of a static Jahn-Teller effect within quasi-isolated [TiF6]3− octahedra. Calculations of the Madelung part of the lattice energy were performed to discuss the chemical bonding.