for: electrons (or other charged particles)
in: a solid
is: a set of narrowly separated energy levels that the electrons (or other charged particles) may occupy. (Note that the energy bands are a property of the solid as a whole, not of the individual atoms within the solid.) [P11.4]
is formed: from an energy level for the electrons in individual atoms, which becomes split and broadened by the influence of other nearby atoms in the solid. [P11.4]
is usually separated: from other bands, just as the individual electron energy level from which it is derived is separated from other energy levels (though it is also possible for different bands to overlap). [P11.4]
See also, band theory, conduction band and valence band.
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