This highly reactive compound, invariably used in solution with an ether as the solvent, is a reagent in organic synthesis as well as organometallic chemistry.

[3] Methyllithium is both strongly basic and highly nucleophilic due to the partial negative charge on carbon and is therefore particularly reactive towards electron acceptors and proton donors.

In contrast to n-BuLi, MeLi reacts only very slowly with THF at room temperature, and solutions in ether are indefinitely stable.

For example, ketones react to give tertiary alcohols in a two-step process: Nonmetal halides are converted to methyl compounds with methyllithium: Such reactions more commonly employ the Grignard reagents methylmagnesium halides, which are often equally effective, and less expensive or more easily prepared in situ.

In contrast the bulkier cluster (tertiary-butylLi)4, where intercluster interactions are precluded by steric effects, is volatile as well as soluble in alkanes.

Colour code: Li- purple C- black H- white The hexameric form features hexagonal prisms with Li and C atoms again at alternate corners.

Colour code: Li- purple C- black H- white The degree of aggregation, "n" for (MeLi)n, depends upon the solvent and the presence of additives (such as lithium bromide).

These clusters are considered "electron-deficient," that is, they do not follow the octet rule because the molecules lack sufficient electrons to form four 2-centered, 2-electron bonds around each carbon atom, in contrast to most organic compounds.