Elektroneninduzierte topotaktische Zersetzungsreaktionen anorganischer Verbindungen

Abstract

Electron microscopical samples may decompose under the influence of the electron beam. Such reactions are often topotactic. As examples, the electron induced decompositions of tin(IV)-sulfide and of copper(II)-hydroxide are discussed, of which the first is controlled by epitaxy on inner lattice planes, while the latter starts by nucleation on specific atom rows. A comparison with results on numerous other electron induced decomposition reactions shows that most of these are two or even only one dimensionally controlled. Therefore it becomes obvious that a three dimensional relation between the crystal structures of the compounds involved is by no means a necessary condition for topotaxy.
The differences between electron induced and thermal decompositions show that the former are not due to beam heating of the sample only, but that specific ionisation processes must be involved.