What are organometallic compounds?
Organometallic chemistry is the study of chemical compounds containing bonds between carbon and a metal. Since many compounds without such bonds are chemically similar, an alternative may be compounds containing metal-element bonds of a largely covalent character. Organometallic chemistry combines aspects of inorganic chemistry and organic chemistry. Organometallic compounds are widely used in homogeneous catalysis.
The metal-carbon bond in organometallic compounds is generally of character intermediate between ionic and covalent. Primarily ionic metal-carbon bonds are encountered either when the metal is very electropositive (as in the case of Group 1 or Group 2 metals) or when the carbon-containing ligand exists as a stable carbanion. Carbanions can be stabilized by resonance (as in the case of the aromatic cyclopentadienyl anion) or by the presence of electron-withdrawing substituents (as in the case of the triphenylmethyl anion).
On the other hand, the ionic character of metal-carbon bonds in the organometallic compounds of transition metals, other metals, and metalloids tends to be intermediate, owing to the middle-of-the-road electronegativity of such metals.
Organometallic compounds with bonds that have characters in between ionic and covalent are very important in industry, as they are both relatively stable in solutions and relatively ionic to undergo reactions. Two important classes are organolithium and Grignard reagents.