in a way that involves two atoms sharing one or more pairs of electrons that hold them together

Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. 二氧化碳是由两个氧原子与一个碳原子共价结合而成的化合物。

Some covalently bonded substances react with water rather than dissolving in it.

Heparin is strongly acidic because of its content of covalently linked sulphate and carboxylic acid groups.

Some small molecules inhibit enzyme activity by bonding covalently to specific amino acid side-chains.