Studies in Mössbauer spectroscopy. Part I. Interpretation of quadrupole splitting data for tin(IV) compounds

Abstract

Mössbauer spectroscopic data for a range of substituted alkyl- and aryl-tin(IV) compounds are presented. In presumably isostructural series of these and other compounds, the quadrupole splitting increases in the orders: alkyl ∼ aryl ∼ CHCH₂ < C₆Cl₅∼ C≡CPh < C₆F₅∼ CF₃ < SSnR₃ < OSnR₃, I < Br < Cl < F, and C₆H₅ < CHCH₂ < CH₂CH₃. These orderings are discussed in terms of the nature of the tin–ligand bonds and it is concluded, in contrast to earlier interpretations, that imbalance in the polarity of the σ-bonds is the dominant factor in determining the size of the quadrupole splitting. The importance of the geometrical arrangement of the ligands is stressed; this effect may be assessed from the point-charge model.