Pb 3 Al 2 F 12 : Crystal structure of a cyclo ‐fluoroaluminate related to Ba 3 Al 2 F 12

Pb 3 Al 2 F 12 is a fluorometalate obtained in single‐crystal form by hydrothermal synthesis. It crystallizes in the monoclinic system, space group P 2 1 /n, with a = 9.435(6) Å, b = 9.610(5) Å, c = 10.100(9) Å, β = 90.59(5)°, V = 915.7(2) Å 3 , Z = 4. The structure was solved from single crystal using 3 044 unique reflections (MoKα, λ = 0.71073 Å), R = 0.0463, R w = 0.0465. The structure exhibits isolated tetrameric groups of octahedra encaged in a subnetwork of independent fluoride polyhedra and is related to that of Ba 3 Al 2 F 12 . A discussion about the existence and the structure of A 3 M 2 F 12 compounds is given.