The vinyloxonium cation, documentclass{article}pagestyle{empty}begin{document}${rm CH}_{rm 2} = {rm CH - }mathop {rm O}limits^{rm + } {rm H}_{rm 2}$end{document}, a stable [C2H5O]+ species in the gas phase

The charge stripping mass spectra of [C₂H₅O]⁺ ions permit the clear identification of four distinct species: documentclass{article}pagestyle{empty}begin{document}${rm CH}_{rm 3} - {rm O - }mathop {rm C}limits^{rm + } {rm H}_{rm 2}$end{document}, documentclass{article}pagestyle{empty}begin{document}${rm CH}_{rm 3} - mathop {rm C}limits^{rm + } {rm H - OH}$end{document}, and documentclass{article}pagestyle{empty}begin{document}${rm CH}_{rm 2} = {rm CH - }mathop {rm O}limits^{rm + } {rm H}_{rm 2}$end{document}. The latter, the vinyloxonium ion, has not been identified before. It is generated from ionized n-butanol and 1,3-propanediol. Its heat of formation is estimated to be 623±12 kJ mol^?1. The charge stripping method is more sensitive to these ion structures than conventional collisional activation, which focuses attention on singly charged fragment ions.