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Re: IONS



Gary Karshner wrote:

First- glass as opposed to quartz contains a "flux" impurity that
lowers the
melting point, and it may well be the impurity that supplies the
conduction
electrons.

I also found, after responding to Chuck's message, that most glasses
are only about 70% pure silica, "sometimes, erroneously called fused
quartz". The rest are various oxides. Some of these are semiconductors
and they give glass "electronic conductivity", as opposed to more
common "ionic conductivity". The electric conductivity can be as low
as 500 ohms-cm. Such glasses are not dielectric materials to which I
was initially referring. A rod made from pure SiO2 would not behave
in the way described by Chuck Britton. What were chemists trying to
show by performing the demo?

I have a related question. Suppose that a pure dielectric, such as SiO2,

is "loaded" with a uniform cloud of net negative charge. This can be
done, for example, by stopping beta particles inside. Would the cloud
remain uniform (as the charge density goes up) or will charges be
drifting toward the surface, as in metals, due to mutual repulsion?
What is the maximum possible charge density (order of magnitude)
inside a solid?
Ludwik Kowalski