Calorimetric approach to some current tropics in solid state chemistry: spin transitions, metastability, and oxides with variable formal oxidation state of the metal

High-temperature adiabatic calorimetry enables accurate determinations to b e made of the heat capacity of key materials and, furthermore, is indispens able for development of high-temperature enthalpy standards for differentia l scanning calorimetry. Adiabatic calorimeters may, however, be used as ver satile instruments for studies of energetic and kinetic aspects of reaction s as well. This paper summarizes aspects of the methodology and presents ex amples of specific applications of adiabatic calorimetry in solid state che mistry. Calorimetric approaches to spin transitions, metastability, and red ox reactions in oxides with variable oxidation state of the metal are brief ly reviewed. (C) 1998 Academic Press.