Multinuclear ions of ferrocene [Fe n (C 5 H 5 ) n +1 ] + ( n = 2, 3 and 4) in the gas phase identified by mass spectrometry

Under methane chemical ionization conditions, multinuclear ions of ferrocene [Fe n (C 5 H 5 ) n +1 ] + ( n = 2, 3 and 4), resulting from the ion/molecule reactions in the gas phase, were detected by mass spectrometry. Structures for these ions are elucidated, according to their mass‐analyzed ion kinetic energy spectra, to be triple‐, quadrupole‐, and quintuple‐decker sandwiches, respectively, and the formation pathways for them are also discussed.