Compounds that contain atleast one carbon metal bond are called organometallic compound. Hence, based on above definition methyl lithium is an organometallic compound. In other chemical compounds carbon is notlinked with metal.

Organometallic compound is (b)as it contains metal-carbon bonds.In others, direct link of carbon with metal is not present.

In one case, on electrolysis of aqueous solution, the complex ion of cobalt [i.e.,{Co(NH₃)₆}³⁺] of the complex[Co(NH₃)₆][Cr(NO₂)₆] moves towards cathode(i.e.,negative electrode) and on this electrode finally cobalt would be deposited.

In another case, on electrolysis of aqueous solution,the complex ion of chromium[i.e., {Cr(NH₃)₆}³⁺] of the complex[Cr(NH₃)₆][Co(NO₂)₆] moves towards cathode(i.e.,negative electrode) and on this electrode chromium would finally be deposited.

Due to some backbonding by sidewise overlapping between d-orbitals of metal and p-orbital of carbon, the Fe–C bond in Fe(CO)₅ has both σ and π character.

The complex formation is a characteristic of d-block elements.Lead is a p-block element hence does not forms complex compounds.

The chlorophyll moleculeplays an important role in photosynthesis, contain porphyr in ring and the metal Mg not Ca.

The number of carbon atom found in π bonded organometallic compounds is indicated by the greek letter 'η' with a number. The prefixes η², η⁵ and η⁶ indicate that 2, 5 and 6 carbon atom are bound to the metal in the compound.(CH₃)₄ Sn does not involve any pi (π) bond formation. This is a σ bonded organometallic compound.