Electron spin resonance and Raman spectra of [ReOF5]– and related species in aqueous hydrofluoric acid

Abstract

Raman spectra and electron spin resonance measurements on the products of partial hydrolysis of rhenium hexafluoride in aqueous hydrofluoric acid show that the main species is green [ReOF₅]^–. Assignments of the observed fundamental frequencies from the Raman spectra are as follows: 1008 (ν₁), 736 (ν₂), 700 (ν₈), 590 (ν₅), 575 (ν₃), 387 (ν₁₀), 370 (ν₇), 330 (ν₄), 298 (ν₉), and 233 (ν₆) cm^–1 which confirms the expected C_4ν symmetry. The e.s.r. parameters are: g_∥= 1·72, g_⊥= 1·74, A_∥(Re)= 0·0960 cm^–1, A_⊥(Re)= 0·0500 cm^–1, and |Q′|= 0·0045 cm^–1, together with fluorine hyperfine coupling. The bonding parameters are β₁= 0·78, β₂= 0·85, and ε= 0·92 showing considerable covalency. A transient blue species is considered to be an oxygen- or fluorine-bridged polymer.