Metal carbonyls synthesis, physical properties and structure

Worked example 23.2 18-Electron rule metal-metal bonding 

Metal-metal bonding in mnltinnclear species is not always clear-cut. Solely on the basis of the 18-electron rule, suggest whether (n -Cp)M(p-PPh2)2Ni(ii -Cp) might be expected to contain a metal-metal bond. 

The formula is instructive in terms of drawing a structure, except in respect of any M—M bond. Thus, we can draw as an initial structure  

Note that in all such examples, a prediction about the presence or not of the M—M bond assumes that the 18-electron rule is obeyed. Bridging ligands often play a very important role in supporting a dimetal framework. 

4 Metal carbonyls synthesis, physical properties and structure 

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Metal carbonyls synthesis, physical properties and structure 899 Table 24.3 Neutral, low-nuclearity (metal carbonyls of the (f-block metals (dec. = decomposes). 

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