SF4 center dot N(C2H5)(3): the first conclusively characterized SF4 adduct with an organic base

Sulfur tetrafluoride and triethylamine react at low temperatures to form a 1 : 1 adduct. The unambiguous characterization of the SF4 center dot N(C2H5)(3), which is only stable at low temperature, proves the Lewis acid property of SF4 towards organic Lewis bases. The S-N bond has a length of 2.384(2) angstrom and is an archetypical example of a dative S-IV -> N bonding modality.