Acetylide

In chemistry, an acetylide is a compound that can be viewed as the result of replacing one or both hydrogen atoms of acetylene (ethyne) HC≡CH by metallic or other cations.

Calcium carbide is an important industrial compound, which has long been used to produce acetylene for welding and illumination.

[3] Other acetylides have the metal bound to the carbon atom(s) by covalent bonds, being therefore coordination or organometallic compounds.

Evidence for this ionic character can be seen in the ready hydrolysis of these compounds to form acetylene and metal oxides, and by solubility in liquid ammonia with solvated −C≡C− ions.

[4] The −C≡C− ion has a closed shell ground state of 1Σ+g, making it isoelectronic to a neutral molecule N2, which may afford it some gas-phase stability.

[5] Some acetylides, particularly of transition metals, show evidences of covalent character, e. g. for being neither dissolved nor decomposed by water and by radically different chemical reactions.

In organic synthesis, acetylides are usually prepared by treating acetylene and alkynes with organometallic[12] or inorganic[11] Classically, liquid ammonia was used for deprotonations, but ethers are now more commonly used.