Magnetic susceptibility is a measure of how a substance responds to an external magnetic field. In general, substances can be classified as diamagnetic, paramagnetic, or ferromagnetic based on their magnetic susceptibility.Oxygen O2 is a paramagnetic molecule, meaning it has unpaired electrons that can align with an external magnetic field, resulting in a positive magnetic susceptibility. The magnetic susceptibility of oxygen is approximately +3444 x 10^-6 cm^3/mol.Carbon dioxide CO2 , on the other hand, is a diamagnetic molecule, meaning it has no unpaired electrons and its electrons are all paired up. Diamagnetic substances have a negative magnetic susceptibility, as they are slightly repelled by an external magnetic field. The magnetic susceptibility of carbon dioxide is approximately -16.5 x 10^-6 cm^3/mol.In comparison, the magnetic susceptibility of oxygen is significantly higher and positive compared to that of carbon dioxide, which is lower and negative. This difference in magnetic susceptibility is due to the presence of unpaired electrons in oxygen, making it paramagnetic, while carbon dioxide is diamagnetic with no unpaired electrons.