Electrical Properties

Solids show an astonishing spread of electrical conductivities — covering about 27 orders of magnitude, from roughly $10^{-20}$ to $10^{7}\ \Omega^{-1}\,\mathrm{m^{-1}}$. On this basis solids are grouped into three types:

• Conductors — conductivity between about $10^{4}$ and $10^{7}\ \Omega^{-1}\,\mathrm{m^{-1}}$. Metals, with conductivities of the order of $10^{7}\ \Omega^{-1}\,\mathrm{m^{-1}}$, are good conductors.
• Insulators — very low conductivity, between about $10^{-20}$ and $10^{-10}\ \Omega^{-1}\,\mathrm{m^{-1}}$. …