Anionen in der Gasphase

Important general structural and energetic characteristics are provided for atomic and molecular anions, before spectroscopic quantities such as electron affinity are defined to characterize stable anions. Prepared in this way one encounters atomic anions in the first scope. After a short prelude with diatomic molecular anions an attempt is made to juxtapose anions of alkanes and silanes and the corresponding olefinic systems. Associated with these species there is the phenomenon of short‐lived resonances on the one hand, while on the other hand the anions can be stabilized by appropriate geometry distortions or substituents. Distonic radical anions, where the radical‐center does not coincide with the charge center, or dipolarly‐bound anions, where the extra electron is very feebly bound, are not very well known hitherto, but have a wide field of application in organic chemistry. The presentation of solvated anions with a special focus on S N 2‐reactions completes this area. Only a few examples document the unique double‐Rydherg anions, which are characterized by a pair of electrons bound loosely to a cationic core. The multiply‐charged anions are shown to have a very wide field of application in the sequel. The initial “disappointment” that the well‐known small textbook‐polyanions do not exist in the gas phase is followed by the apothegm “more space for charge separation”. With this key‐ note a wide field for organic (carbonic acids, carbon clusters) as well as inorganic compounds (complexes) is opened.