Why is oxygen not paramagnetic in gaseous state, but is in liquid and solid states?
Something that is paramagnetic means that it is weakly attracted to the poles of a magnetic field, but it itself does not retain any magnetic properties once it is beyond that magnetic field. Oxygen, no matter what its state, is paramagnetic. In solid and liquid oxygen, the magnetic effect is measurable, but in a gas, the molecules of oxygen possess ample energy of motion to overcome the weak magnetic influence. See complete details at the links: