ABSTRACT
This chapter describes the methods used to rationalise and understand the structures of transition metal carbonyl clusters. There is not one single method that works for all compounds, but all are based on electron counting procedures. A ll the important methods are described, and it w ill become apparent where the different procedures should be applied. It w ill also be shown how certain clusters can be viewed in different ways, and in such cases, it is often possible to use more than one electron counting scheme to rationalise their structure.
