(1) It has been ascertained that there exists only one addition compound, perovskite (CaO·TiO2), in the system CaO and TiO2. As for the unit cell size of pure perovskite, a=7.615Å should be given as correct, which is twice as great as the value hitherto given. (2) CaO·TiO2 has been proved to form a solid solution with the two components, the range of which spreads approximately from a slight excess of TiO2 to CaO:TiO2=3:2, and in which the lattice constant is enlarged and the crystal form deviates from cubic with the increase of the content of CaO. (3) At the early stage of the solid reaction of this system, the product is richest in TiO2 within the possible range of the solid solution; the solid solution rich in CaO may be formed gradually when an excess of CaO is present. (4) It has been concluded that, although there exists a rapid initial reaction, a further reaction is controlled by the diffusion of the two components through the reaction product. The energy of activation of the diffusion process has been calculated as 30.3 kilocalories per mole. (5) It has been found that the reaction products turn light red by the action of light; some observations thereon have been made.
(1) It has been shown that the thermal diffusion apparatus of Clusions and Dickel with a comparatively large wall distance is suitable for the determination of the thermal diffusion coefficient of liquid solutions. (2) The separations of some inorganic solutions (HCl, H2SO4, NaCl, KCl, NH4CI, Na2CO3, Na2SO4, CuSO4 and NaOH) have been carried out. (3) The observed results have been shown to be in concordance with the theory of Debye and to give reasonable Soret constants if com？ared with those, hitherto, directly measured. (4) The thermal diffusion (coefficient of each solution has been determined, and from these values the nature of the thermal diffusion has been discussed to some extent.