Questions about the 18e rule and M-M bond order in Organometallic Complexes

Using the 18 electron rule determine the number of M-M bonds in the following polynuclear complexes

Not sure what the 18 electron rule is, please follow this quide (under construction)

Need help using the 18 electron rule to work out the number of M-M bonds, please follow this quide

University of Sheffield has a www chemical calculator which will check this for you. ChemPuter