Standard ball-and-stick models of O2 do not use a curved bond. Reliable chemistry sources describe oxygen as linear and represent the O–O bond with a straight connector. If a classroom model appears curved, that usually reflects a bent or worn piece in a particular kit, or an intentional kit design choice, not a general fact that O2 models are curved because of plastic technical problems.

Standard chemistry definitions do not support this statement. O2 is a diatomic molecule, and diatomic molecules are classified as linear because two nuclei define a straight line. References to electron density or vibration do not change the formal molecular geometry to bent.