Determination of Adsorption enthalpies and entropies of Inorganic Halides by Temperature Programmed Gas Chromatography

The possibilities of using temperature-programmed gas-solid chromatography· for the determination ofadsorption enthalpies and entropies of inorganic chlorides are investigated. This method is suitable, if data oflimited accuracy are acceptable, whereas for more precise data isothermal gas chromatography is recommended. The advantage of temperature-programmed experiments is that simultaneous investigations can be made ofcompounds with very different volatilities. The results of these investigations support the picture of "surface complexes" bet\veen the adsorbed molecules (metal halides or oxyhalides, e.g., ReCls _ SnCl.s, PoCl.s. etc.) and the adsorbent (alkali metal halides. SiO.!).