Diamagnetic

diamagnetic [¦dī·ə·mag′ned·ik]

(electromagnetism)

Having a magnetic permeability less than 1; materials with this property are repelled by a magnet and tend to position themselves at right angles to magnetic lines of force.

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Diamagnetic 

a substance that becomes magnetized against the direction of an external magnetic field. In the absence of an external magnetic field a diamagnetic is nonmagnetic. Upon exposure to an external magnetic field each atom of a diamagnetic acquires a magnetic moment j (each mole of the substance acquires a total moment J) proportional to the field intensity H and directed against the field. Therefore, the magnetic susceptibility x = J/H is always negative for diamagnetics. The diamagnetic susceptibility χ is small with respect to absolute magnitude and is weakly dependent on both the magnetic field intensity and the temperature (seeTable 1, where xis the susceptibility of 1 mole).

Table 1. Magnetic susceptibility of certain diamagnetics (under normal conditions)
	X x 10-6
Nitrogen (N2)...............	-12.0
Hydrogen (H2)...............	-4.0
Germanium (Ge)...............	-7.7
Silicon (Si)...............	-3.1
Water, liquid (H2O)...............	-13.0
Table salt (NaCI)...............	-30.3
Acetone (C3H6O)...............	-33.8
Glycerol (C3H8O3)...............	-57.1
Naphthalene (C12H8)...............	-91.8(avg.)

Diamagnetics include silicon, phosphurus, bismuth, zinc, copper, gold, silver, the inert gases, nitrogen, and hydrogen. Many organic and inorganic compounds are diamagnetic.