ULTRASONIC VELOCITY AND DENSITY-MEASUREMENTS OF MOLTEN CUCL-CUBR MIXTURES

The ultrasonic velocity, sound attenuation and density measurements ha ve been carried out for molten Cu(Cl1-xBrx) mixtures at temperatures f rom the melting points to about 800-degrees-C to investigate the therm odynamic and dynamical properties. The adiabatic compressibility of th is system has obtained from the observed ultrasonic velocity and densi ty. The observed compressibility has an interesting concentration depe ndence of positive deviation from linear one and has the maximum aroun d Cu(Cl0.2Br0.8) which suggests large fluctuations in the molten mixtu res compared with pure molten CuCl and CuBr. The sound attenuation sho ws large temperature dependence around x=0.2 and 0.8. We discuss the t hermodynamic and dynamical properties of the molten mixtures from a vi ew point of chemical bond, taking the difference of ionicity between C l and Br into account.