BENZYLPYRIDINIUM IONS AND THEIR DERIVATIVES 2.1.1. Fragmentation pathways of benzylpyridinium ions Benzylpyridinium ions were initially chosen for internal energy distribution determinations because the C-N simple bond cleavage, resulting in a benzylium ion and pyridine, is the predominant fragmentation reaction . Several studies focused on other fragmentation pathways of benzylpyridiniums, and how they should be taken into account in the survival yield method.