Structure and properties of the KF-KCl-KBF4 melts

On the basis of the phase diagram, density, conductivity, and viscosity measurements as well as the direct spectroscopic analysis, the structure of the KF-KCl-KBF4 melts has been elucidated. From the physicochemical analysis it follows that, a significant ternary interaction of all anions present in the melt takes place. The deviation from the ideal behaviour is due to the break off of the relatively weak B-F-B bonds between the BF4- tetrahedra, the mixing of anions with different ionic radius, as well as the exchange of the fluorine atoms in the BF4- tetrahedra for the chlorine ones. The presence of [BF4-nCln](-) anions was confirmed by means of the IR spectroscopy of quenched samples.