Preparation of metal carbonyls and organometallic compounds

Metal atoms in compounds containing carbon metal bonds frequently 120 

Metal carbonyls were first prepared by mond by the direct reaction of gaseous carbon monoxide with finely divided metals. Iron, cobalt, and nickel 

A variety of metal carbonyls are known. The eighteen-electron rule and Sidgwick s effective atomic number rule (Section 2.3) are very successful in explaining their stoichiometries. Simple monomeric carbonyls are expected for transition metals with even atomic numbers Cr(CO)6, Fe(CO)s, Ni(CO)4. The heavier members of the Cr and Fe families also form monomeric carbonyls of the predicted stoichiometry. 

Transition metals with odd atomic numbers cannot achieve the expected FAN in monomeric compounds. In cases where carbonyls of these elements are known, the compormds contain more than one metal atom and metal-metal bonds these effectively contribute one extra electron to each metal Mn2(CO)io, Co2(CO)s. Many polynuclear metal carbonyls are known. The largest metal cluster that has been characterized is a polynuclear platinum carbonyl anion, 

In 1959, V(C0)6 was prepared. It is a black paramagnetic solid that decomposes at 70°C. It is the only stable metal carbonyl containing one metal atom that does not obey the eighteen-electron rule. It is a seventeen-electron system which is readily redueed to the stable eighteen-electron anion [V(C0)6] , reaction (2). The seventeen-eleetron V(C0)6 is very reactive for example, it 

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