STABILITY OF NIOBIUM PENTACHLORIDE SOLUTIONS IN CHLORIDE MELTS

Dissolution of niobium pentachloride in molten alkali chlorides was studied in NaCl-KCl, NaCl-CsCl, NaCl-KCl-CsCl and LiCl-KCl based melts and the progress of the dissolution was followed by in situ spectroscopy measurements and oxidimetry. The obtained results indicate that NbCl6- species constituted the main product of this reaction. At relatively high niobium concentrations in the melt NbCl6-, however, partly decomposed yielding NbCl62- and chlorine gas. The influence of temperature and average radius of solvent cation on concentration of formed niobium (IV) species were investigated