Chemical Synthesis of Elemental Fluorine

摘要

The purpose of this communication is to report the first purely chemical synthesis of elemental fluorine in significant yield and concentration. This synthesis is based on the fact that thermo-dynamically unstable high-oxidation-state transition-metal fluorides can be stabilized by anion formation. Thus, unstable NiF4, CuF4, or MnF4 can be stabilized in the form of their corresponding MF6(2-) anions. Furthermore, it is well-known that a weaker Lewis acid, such as MF4, can be displaced from its salts by a stronger Lewis acid, such as SbF5. If the liberated MF4 is thermodynamically unstable, it will spontaneously decompose to a lower fluoride, such as MF3 or MF2, with simultaneous evolution of elemental fluorine. The chemical generation of elemental fluorine might be accomplished by a very simple displacement reaction, provided a suitable complex fluoro anion is selected which can be prepared without the use of elemental fluorine and is derived from a thermodynamically unstable parent molecule. The salt selected for this study was K2MnF6.