Zur Kristallstruktur von Ba3Al2F12

Concerning the Crystal Structure of Ba₃Al₂F₁₂ Preparing BaMnAlF₇ we obtained single crystals of Ba₃Al₂F₁₂ as a by‐product (a = 1020.3(2), b = 988.5(1), c = 952.2(1) pm, space group Pnnm, Z = 4). The redetermination confirmed the structure already known, but improved the results (R₁′ = 0.028 and wR₂ = 0.06 for 1908 and 2717 reflections, resp.). An interpretation is given for the relation of distances within the tetrameric anion Al₄F₂₀]^8— (average Al—F: 180, 1 pm). The construction of the cationic frame Ba₃F₂]⁴⁺ is discussed.