“…However, the isolation of the subsequent water-soluble A 2 [ReF 6 ] salt has shown to be challenging. 4,5 Recently, detailed procedures for the preparation of K [ReF 6 ] has been studied by X-ray absorption spectroscopy, 7 thermal gravimetric analysis 14,15 and was used as a precursor for preparing materials with remarkable magnetic properties, 9,11,12 up to now there is no available single crystal Xray data of the salt. In salts containing the [ReX 6 ] 2À (X ¼ F, Cl, Br, I) anions, the Re(IV) ion (5d 3 ) forms a hexakis-monodentate coordination with the halogen atoms resulting in either a regular or slightly distorted octahedral geometry.…”