A coordination bond (also known as a dative covalent bond) forms when both electrons in the shared pair come from the same atom.

An electrophile is a species that accepts an electron pair to form a covalent bond.

Lewis acid is a species that accepts an electron pair. It is often electron-deficient, meaning it has an incomplete octet or a positively charged center that makes it eager to gain electrons.

Lewis base is a species that donates an electron pair. It is electron-rich, often possessing a lone pair of electrons that can be shared.

A molecule or ion that donates a lone pair of electrons to a central metal ion to form a coordination bond.

A nucleophile is an electron-rich species that donates a pair of electrons to form a covalent bond. The term “nucleophile” originates from the Greek words nucleus (meaning core) and philos (meaning loving), indicating its affinity for positively charged or electron-deficient centers.