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ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Published monthly
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Cryoscopy of B203 in Molten Alkali Metal Fluorides
M. Makyta
Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-842 36 Bratislava
Abstract: The mechanism of dissolution of boron oxide in LiF, NaF, and KF and the ionic structure of created molten mixtures were studied by the cryoscopic method. The investigation was carried out in B203 mole fraction region from 0 to 5 mole %. The results of cryoscopic measurements have been confirmed by X-ray analysis and by infrared spectroscopy as well. It was found that alkali metal tetraborate, alkali metal metaborate, and boron trifluoride are created in the molten systems LiF-B203 and NaF-B203. Gaseous BF3 is evaporated from the melt. Except alkali metal cations the anions F-, BO2-, and B4O72- are present in the melt. In the system KF-B203 boron oxide reacts with KF under the formation of potassium tetraborate and potassium tetrafluoroborate. The ionic structure of created molten mixtures is given by the presence of potassium cations and anions F-, B4O72-, and BF4-. The presence of the metaborate anions, BO2-, was not proved by spectral methods, however, it cannot be excluded in melts with low concentration of boron oxide.
Full paper in Portable Document Format: 475a306.pdf
Chemical Papers 47 (5) 306–309 (1993)
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