OsO3F2 and OsO2F4, Preparation and Crystal Structures

The new method for preparing OsO3F2 is presented. Its crystal structure reveals a polymeric chain structure with distorted octahedral geometry for the OsO3F3 units and symmetrical, non‐linear fluorine bridges. The OsO3F3 unit has a facial geometry. This structure is not in accord with predictions on the molecular structure of OsO3F2. OsO2F4, obtained from KrF2 and OsO4, crystallizes in the space group P61 forming a sixfold helical chain arrangement of nearly octahedral OsO2F4 molecules. Oxygen or fluorine atoms are partially disordered. The cis orientation of the two oxygen atoms is established by means of NMR, vibrational spectroscopy, and X‐ray data.