Zur Kristallstruktur von CaFeF₅^†

On the Crystal Structure of CaFeF₅

Single crystals of CaFeF₅ were obtained by heating a mixture of the component fluorides at 860°C for 12 d (a = 549.2(1), b = 1007.6(2), c = 759.9(2) pm, β = 110.02(3)°; space group P2₁/c, Z = 4). The X-ray structure redetermination of a twinned specimen confirmed the chain structure of octahedra sharing trans corners already known. But the anomalies reported earlier were removed and less distorted [FeF₆] octahedra and [CaF₇] pentagonal bipyramids were found, the distances of which are split within the usual range around mean values of Fe—F: 192.4 and Ca—F: 233.1 pm.