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 C_p 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.