Breakdown of Bond Length-Bond Strength Correlation: A Case Study

Stronger does not automatically mean shorter! That the correlation between bond lengths and bond strengths intuitively expected and frequently applied in interpretations of molecular structure is not always valid, is confirmed by bond lengths, dissociation energies, and force constants computed at state-of-the-art ab initio levels for a series of fluorine-substituted stannanes Sn2H6−nFn. The lack of correlation is attributed to hybridization defects (decrease of the p/s hybridization ratio with increasing fluorine substitution).