Kind of magnetism characteristic of materials that line up at right angles to a nonuniform magnetic field and that partly expel from their interior the magnetic field in which they are placed. In most materials, the magnetic fields of the electrons balance each other and add up to zero. However, when placed in an external magnetic field, the interaction of this field with the electrons induces an internal field in the opposite direction. The substance can then be weakly repelled by magnetic poles. Examples of diamagnetic substances include bismuth, antimony, sodium chloride, gold, and mercury.

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