S 83 Stepanov, V. P. Sound Velocities for Dissolving AgI + LiCl Melts / V. P. Stepanov, V. I. Minchenko // Journal of Chemical & Engineering Data. - 2014. - Vol. 59, № 11. - С. 3888-3893 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): УЛЬТРАЗВУК -- СКОРОСТЬ ЗВУКА -- ФАЗОВЫЙ ПЕРЕХОД -- ТЕМПЕРАТУРНЫЕ ЗАВИСИМОСТИ Аннотация: The ultrasonic velocities of a molten stratified mixture at a molar ratio of 0.3AgI and 0.7LiCl (the composition corresponding to the top of the miscibility gap) were measured along the saturation line over a wide temperature range using the pulse method to establish the characteristics of mixing salts comprising different chemical bonds. It is shown that the coefficients of the temperature dependences for the sound velocities in the coexisting phases have opposite signs as a result of the superposition of the temperature and concentration factors. It is found that the difference, Δu, between the magnitudes of the sound velocities for the coexisting phases decreases with increasing temperature and becomes zero at 1250 K. This temperature corresponds to the critical phase transition point, Tc. The temperature dependence of the sound velocity difference, Δu, for the system studied is described by the equation Δu ≈ (Tc – T)β, where β = 0.900, which is close to the value 0.896 obtained for the previously investigated AgI+NaCl melt but is less than the value found for alkali halide melts (β = 1.02), in which long-range Coulomb forces between ions prevail. The results are discussed in terms of the peculiarity of the chemical bond in silver iodide. |