ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Surface Tension of Melts of the System KF—KCl—KBF₄

Ž. Lubyová, V. Daněk, and D. K. Nguyen

Institute of Inorganic Chemistry, Slovak Academy of Sciences. SK-842 36 Bratislava

Abstract: The surface tension of the molten system KF-KCl-KBF₄ has been determined using the maximum bubble pressure method. The error in the surface tension measurement was estimated to be +/- 1%.In the investigated system the surface tension decreases with increasing content of KBF₄, which is apparently due to the surface adsorption of the BF₄^- anions having stronger covalent character of bands than the pure ionic KF and KCl melts. Moreover, the exchange of fluorine atoms in the BF₄^-tetrahedra by the chlorine ones leads to the presence of the [BF_4-nCl_n]^- mixed anions which are. adsorbed on the melt surface as well.The calculated surface entropy in the binary systems has a maximum at the 1 : 1 mole ratio mixtures which increases from the system KF-KCl through KF-KBF₄ to KCl-KBF₄. This indicates the simpler structure for the melts of pure components and of the system KF-KCl and the most complex one for those of the system KCl-KBF₄.

Full paper in Portable Document Format: 512a78.pdf

Chemical Papers 51 (2) 78–83 (1997)