The Application of Low-Temperature Calorimetry to Some Contemporary Problems in Solid State Chemistry

Abstract

The contribution which low-temperature calorimetry can make to contemporary problems in solid state chemistry is illustrated, first by showing how the heat capacity-temperature curve of RbAg4I5 reflects the growing disorder of the silver ions, which gives this substance its remarkably high electrical conductivity. The use of Cp data to obtain information about movement in a crystal is then considered for the particular case of the restricted rotation of the ammonia ligands in the complex cations in the salt Co(NH3) 6Cl3. There follows a review of the polymorphism and magnetic ordering in the layer compounds (RNH3) 2MX4 where R = an alkyl group, M- metal, X halogen. Finally, the entropies of transition in orientational order-disorder transitions are considered, with special reference to recent work on metallic nitrites.