Oxygen typically forms two bonds. This is because oxygen has six valence electrons and needs two more electrons to complete its outer shell, which usually results in forming two covalent bonds, such as in water (H₂O) where oxygen forms two single bonds with hydrogen atoms

. However, oxygen can sometimes form three bonds in special cases, but this usually involves a positive charge on the oxygen atom, such as in the hydronium ion (H₃O⁺). In this case, oxygen forms three bonds due to one of its lone pairs forming a coordinate (dative) bond with a proton (H⁺), resulting in a positively charged species called an oxonium ion

. In summary:

• Normally, oxygen forms two bonds to satisfy the octet rule.
• Oxygen can form three bonds when it carries a positive charge, as in H₃O⁺.
• Oxygen rarely forms more than two bonds without a formal charge.

This is consistent with the general bonding pattern of oxygen in most compounds