Single electron transfer electropositive metals

A number of radicals may be formed by one-electron transfer redox reactions using a metal ion. These may be either oxidations in which a transition metal ion such as iron(lll) accepts a single electron from the organic substrate to become iron(ll), or the reaction may be a reduction in which a strongly electropositive metal such as sodium donates an electron to the substrate. 

At the end of the description of the rare earth metal carbide halides it seems worthwhile to summarize some facts. These compounds contain single C atoms, or Cj entities with C-C single and double bonds. The kind of species seems entirely related to the number of residual valence electrons at the metal site. As we are dealing with electropositive metals, these electrons will be transferred to MOs of the unit and it is the number of vacant antibonding MOs which determines the kind of carbido species. Thus, the ideas of Atoji (1961) concerning binary carbides can be extended to the rare earth metal carbide halides. A more detailed discussion of the bonding will be given in sect. 3. 

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