page_title: Mass spectral interpretation
section_title: Alkenes
hierarchical_section_title: Mass spectral interpretation / Fragmentation patterns of specific compound classes / Alkenes
caption_attribution_description: English: McLafferty-like rearrangements of alkene molecular ions
context_page_description: Mass spectral interpretation is the method employed to identify the chemical formula, characteristic fragment patterns and possible fragment ions from the mass spectra. Mass spectra is a plot of relative abundance against mass-to-charge ratio. It is commonly used for the identification of organic compounds from electron ionization mass spectrometry. Organic chemists obtain mass spectra of chemical compounds as part of structure elucidation and the analysis is part of many organic chemistry curricula.
context_section_description: Alkenes often produce stronger molecular ion peaks than alkanes due to the lower ionization energy of a pi electron than a σ electron. After the ionization, double bonds can migrate easily, resulting in almost impossible determination of isomers. Allylic cleavage is most significant fragmentation mode due to resonance stabilization. 
  McLafferty-like rearrangements are possible (similar to carbonyl pi bonds). Again, bond migration is possible.
  Cyclohexenes often undergo retro Diels-Alder reactions.
caption: McLafferty-like rearrangements of  alkenes
exif: {}