Abstract: Studies of Mass Spectrometry and Theoretical Calculations on Ion/Neutral Complex IntermediateAuthor Wei Junhua,Liu Zhiqiang,Liu Shuying\=(Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China)\=\=Received 1998-07-04\=\= Abstract \=\;A review is presented on the development of reaction intermediates with increasingly loose structures,ion/neutral complex,in the rearrangements of organic ions in the gas phase and their provement with quantum chemistry calculations.\=\=Key Words: ion/neutral complex,mass spectrometry,reaction intermediate,theoretical calculation