Diethyl ether (${\mathrm{C}}_4{\mathrm{H}}_{10}\mathrm{O}$)

Diethyl ether is the ether $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{OC}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_3$. Its oxygen has lone pairs that can coordinate metal-containing reagents, while its carbon groups provide a relatively nonpolar environment.

This combination explains its role as a solvent in organometallic chemistry. It is a distinct compound from an ester, which contains a carbonyl group adjacent to oxygen, despite some similarity in their names.