Effects of frustration on magnetic molecules: a survey from Olivier Kahn until today

In magnetism, of which molecular magnetism is a part, the term frustration is used rather sloppily. Sometimes one gains the impression that if the reason for some phenomenon is not quite clear then it is attributed to frustration. In this paper a discussion of the effects of frustration that are relevant for the field of molecular magnetism is presented. As will become clear later these effects indeed lead to a variety of unusual magnetic properties. This article surveys the phenomenon of frustration from the point of view of a physicist and tries to reconcile the various views developed in chemistry and physics. Major frustration effects will be discussed.