Relationship between physical properties and structure or chemical bond in perovskite-related oxides has been briefly explained. Magnetic interactions are mainly depending on the local structures of B-O-B sequence and the electronic state of transition metal ions can be controlled by tuning the competing A-O and B-O bonds. Origin of the high temperature quantum paraelectricity in perovskite titanate was explained by the repulsion and Coulomb forces between Ti-O bonds. An example of the control of quantum paraelectricity to quantum ferroelectricity in SrTiO3 was introduced.
Finally, ionic conduction in perovskite-related oxides was briefly reviewed.

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The application of isothermal thermogravimetry (ITG) was introduced as a powerful technique for the case of the determination of oxide ion vacancy concentration in perovskite-type lanthanum chormites, La_1-xCa_xCrO_3-δ. The defect equilibrium was discussed by using both ideal and regular solution models, and it was rather well explained by using regular solution model. The obtained data of defect concentration were very useful to investigate the diffusion mechanism of oxide ion and vacancies in La_1-xCa_xCrO_3-δ. The oxygen vacancy diffusion coefficient (D_v) of La_1-xCa_xCrO_3-δ is constant at T=1273K and it does not depend on the oxygen vacancy concentration (δ). This fact makes it possible to explain the electrochemical oxygen permeation mechanism through a La_1-xCa_xCrO_3-δ dense plate in which the surface reaction of oxygen is considered to be the rate determining step.

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Structure and thermophysical properties at high temperature of pyrochlore-type oxides (A₂B₂O₆O') have been reviewed. The pyrochlore structure can be described as an anion deficient fluorite unit cell and as interpenetrating networks of BO₆ octahedra and A²O' chains or so. As the local structures of the pyrochlore compounds studied by the means of XAFS spectroscopy, the cluster models, which are a part of the pyrochlore structure in the region of the fluorite phase are proposed. Some of the pyrochlore compounds undergo order-disorder transition from pyrochlore to defect fluorite, of which presence and the transition temperature depend on the size of their cations. Some of the pyrochlore compounds indicate oxygen ionic, oxygen ionic-electrical mixed or protonic conductivity. The temperature tendencies of high temperature heat capacity of Ln₂Hf₂O₇ (Ln=Eu and Gd) and La₂Hf₂O₇ are different due to that in the formation enthalpy of defects. The linear thermal expansion coefficients are discussed by the Madelung energy related to the oxygen positional parameter. The thermal conductivity of La₂Zr₂O₇ and Gd₂Zr₂O₇ was also discussed by phonon scattering.

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High temperature thermophysical properties of perovskite-type oxides such as specific heat capacity, thermal expansion, phase transition, thermal conductivity and vapor pressures, have been summarized. The recent results on the model calculations of thermal expansion coefficient and the enthalpy of formation, and isotope effect of transition temperature are also given.

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It was reviewed about effect of rare-earth elements on high-temperature oxidation of metals. One of the explanations for adherence of high-temperature oxide scale was picked up to show an application of thermodynamic data. It was examined thermodynamic adjustability of the explanation. In the process, it showed how the thermodynamic data was used.

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