I know that the different magnetic properties arise from the spin of the electron, I also did some determinations whether a molecule is paramagnetic or diamagnetic (using MO theory), but I don't know how to make a difference between ferromagnetism and paramagnetism. Could someone explain it? And one more: In one text I saw that iron is paramagnetic and in another that it is ferromagnetic, what's true? I suppose that the answer for the first question will reveal the answer of the second one. Thanks in advance!