Note 17 — Chapter XI · THE HALOGENS: CHLORINE, BROMINE, IODINE, AND FLUORINE

The behaviour of platinum to chlorine at a high temperature (1,400°) is very remarkable, because platinous chloride, PtCl2, is then formed, whilst this substance decomposes at a much lower temperature into chlorine and platinum. Hence, when chlorine comes into contact with platinum at such high temperatures, it forms fumes of platinous chloride, and they on cooling decompose, with the liberation of platinum, so that the phenomenon appears to be dependent on the volatility of platinum. Deville proved the formation of platinous chloride by inserting a cold tube inside a red-hot one (as in the experiment on carbonic oxide). However, V. Meyer was able to observe the density of chlorine in a platinum vessel at 1,690°, at which temperature chlorine does not exert this action on platinum, or at least only to an insignificant degree.