Covalent bonding

Covalent bonding occurs in most non-metallic elements and in compounds made from non-metals. Instead of transferring electrons to make ions, atoms share one or more pairs of electrons. Each shared pair is attracted to the positively charged nuclei of the bonded atoms, holding them together.

In a simple molecular substance, covalent bonding produces molecules: separate particles, each containing a fixed number of covalently bonded atoms.