I am studying forms of magnatism, especially related to
the light spectrum. As with Maxwells theory of electromagnetic radiation
being part of the light spectrum, I have been puzzling over whether a
gas or even a liquid can have magnetic moment, or can be capable of
generating a magnetic field if induced by either a permanent or
Does this make sense and if so is it possible?
Any molecule or atom that contains one or more unpaired electrons will be
magnetic. There are different kinds of magnetism, but I'm using the
criterion that if a substance is attracted by a permanent magnet, it is
magnetic. Magnetism can in several ways. The two most common reasons are:
1. The molecule/atom contains an odd number of electrons.
2. The molecule/atom has one or more unpaired electrons as a result of
Hundt's rule that states that atomic orbitals with unpaired
electrons "fill" before atomic orbitals that form electron
pairs. This arises from quantum mechanics for reasons beyond the scope of
Yes, liquids and gases can be magnetic, but there aren't many. Oxygen [O2],
nitric oxide [NO], and nitrogen dioxide [NO2] are the only common
gases/liquids that are magnetic.
As far as I know, a liquid or gas sample cannot have a permanent magnetic
moment. For this to occur, the individual magnetic moments of the atoms or
molecules making up the sample must have some long-range order. In a liquid
or gas, thermal motions constantly disrupt long-range order.
Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
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Update: June 2012