A new variety of PdF2 synthesised by low-temperature reaction in anhydrous HF

A new variety of palladium difluoride has been prepared via a low temperature (LT) process in anhydrous hydrogen fluoride (aHF). Reaction between solutions of Pd(AsF6)2 and CsF in aHF results in the precipitation of the light-brown LT form of PdF2. This phase crystallises in the Pa3 cubic space group with a=532.4(1) pm and can be derived from the fluorite structure. The co-ordination of Pd is: 6F at 217.6(3) pm+2F at 316.8(3) pm. The structural network can be described either as PdF8 rhombohedra sharing edges — as MX8 cubes in the fluorite — or as flattened PdF6 octahedra sharing corners. Each F atom is common to 3 octahedra. The relationships with the fluorite and pyrite structures have been raised. LT-PdF2 is antiferromagnetic, with a Néel temperature evaluated at around 180 K.