Magnetic moment is a measure of the magnetic strength of an atom, ion, or molecule, and it is directly related to the number of unpaired electrons it contains. The more unpaired electrons, the larger the magnetic moment. A species with no unpaired electrons has no net magnetic moment and is diamagnetic, whereas one with unpaired electrons is paramagnetic.

磁矩是原子、离子或分子磁性强弱的量度,它与所含未成对电子的数目直接相关。未成对电子越多,磁矩越大。没有未成对电子的物种无净磁矩,呈抗磁性;而含未成对电子的物种则呈顺磁性。