Anions in the gas phase

Important general structural and energetic characteristics are provided for atomic and molecular anions, before spectroscopic quantities such as elect ron affinity are defined to characterize stable anions. Prepared in this wa y one encounters atomic anions in the first scope. After a short prelude wi th diatomic molecular anions an attempt is made to juxtapose anions of alka nes and silanes and the corresponding olefinic systems. Associated with the se species there is the phenomenon of short-lived resonances on the one han d, while on the other hand the anions can be stabilized by appropriate geom etry distortions or substituents. Distonic radical anions, where the radica l-center does not coincide with the charge center, or dipolarly-bound anion s, where the extra electron is very feebly bound, are not very well known h itherto, but have a wide field of application in organic chemistry. The pre sentation of solvated anions with a special focus on S(N)2-reactions comple tes this area. Only a few examples document the unique double-Rydberg anion s, which are characterized by a pair of electrons bound loosely to a cation ic core. The multiply-charged anions are shown to have a very wide field of application in the sequel. The initial "disappointment" that the well-know n small textbook-polyanions do not exist in the gas phase is followed by th e apothegm "more space for charge separation". With this keynote a wide fie ld for organic (carbonic acids, carbon clusters) as well as inorganic compo unds (complexes) is opened.