Why is KO₂ Paramagnetic?

Potassium superoxide (KO₂) is paramagnetic because it contains unpaired electrons. KO₂ consists of potassium ions (K⁺) and superoxide ions (O₂⁻). The superoxide ion is formed by adding one extra electron to the normal oxygen molecule (O₂). In the molecular orbital structure of O₂, this extra electron remains unpaired in an antibonding orbital called π* 2p. Unpaired electrons create magnetic moments, which makes KO₂ behave like a magnet, hence paramagnetic. Substances with all paired electrons are diamagnetic and do not attract magnets, but KO₂’s unpaired electron causes paramagnetism. This property can be confirmed through molecular orbital theory where the superoxide ion has one unpaired electron leading to paramagnetism.