Recent studies have shown that molten salts can serve as catalysts for methane pyrolysis. Molten alkali chlorides are poor catalysts for pyrolysis but can be activated by the addition of small amounts of salts that contain a reducible cation such as TiCl4 or CrCl3. The activation mechanism involves the back and forth conversion of Ti4+ to Ti3+ or of Cr3+ to Cr2+, caused by thermal fluctuations in the positions of the ions. In this article, we show that there is a correlation between the open cel