# Is Chromium (VI) fluoride be synthesized properly?

Chromium (VI) fluoride, also known as chromium hexafluoride is a possible chemical compound with a chromium atom attached to 6 fluorine atoms. It has been unsuccessfully synthesized a number of times by heating up chromium to 400 °C in a fluorine atmosphere at 20 megapascals of pressure and freezing it as it was formed but this was still a failure as this instead produces chromium (V) fluoride or chromium pentafluoride.Is the following possible?

The predicted reaction was:

$$\ce{Cr + 3 F2 -> CrF6}$$

Instead, the following reaction was happening:

$$\ce{2 Cr + 5 F2 -> 2 CrF5}$$

• I assume that CrF6 is such a strong oxidizer that it easily oxidizes CrF4 to give two CrF5. – Andrew Apr 29 at 21:21
• So what is the question? Your reference states clearly, "CrF6 has yet to be synthesized." It does not state it is impossible. Proving a negative is a bit difficult. – DrMoishe Pippik Apr 29 at 21:21
• Apparently, chromium favors oxide instead of fluoride ligands at such a high oxidation state. – Oscar Lanzi Apr 30 at 1:52
• – Nilay Ghosh Apr 30 at 4:57
• Also, some papers from the late 19th century reported that CrF6 is a deep-red vapor which condensed to a blood-red liquid at low temperature. It is made by reacting lead chromate, calcium fluoride and sulfuric acid($\ce{PbCrO4 + 3CaF2 + 4H2SO4 -> PbSO4 + 3CaSO4 + 4H2O + CrF6}$) It strongly fumes in air and decomposes on contact with water/moisture to form chromium trioxide and hydrofluoric acid. (But then again, this is from a very old source, so this info. maybe outdated). – Nilay Ghosh Apr 30 at 9:48