LAUSR

A simple method is developed for synthesizing [Rh(H2O)6]F3. 3H2O with a yield of 80–90%. 19F, 103Rh, and 17О NMR spectroscopic studies show that the following three processes simultaneously run in the Rh(III)–HF/K–H2O system via parallel routes: the formation of mononuclear aquafluoro complexes [Rh(H2O)6]3+ + F–→ [Rh(H2O)5F]2+ + H2O; the formation of aquahydrofluoro complexes [Rh(H2O)6]3+ + HF2-→ [Rh(H2O)5HF2]2+ + H2O; and hydrolysis of the aqua ion followed by coordination of fluoride ion and condensation of the hydroxo species [Rh(H2O)6]3+ + 2F– → [Rh(H2O)4(OH)F]+ + HF → condensation. [Rh(H2O)6]3+ and [Rh(H2O)5F]2+ are the two species making a major contribution to the material balance at high acidity under equilibrium conditions. Parameters of the 19F NMR spectra of individual complex species are presented.