  Materials may behave in non-expected ways when subject to unexpected
conditions. For example, when Bi was turned into an amorphous phase
(\textit{a}-Bi) unexpectedly it became a superconductor at temperatures below
$10$ K. We provided an explanation as to why \textit{a}-Bi superconducts and
the crystalline (\textit{c}-Bi) had not been found to do so: we computer
calculated their electronic properties and found that \textit{a}-Bi has a
larger electron density of states, eDoS, at the Fermi surface than
\textit{c}-Bi and this explained the phenomenon. We even predicted an upper
limit for the superconducting $T_c$ of the crystalline phase, which was
experimentally corroborated within the following year. We now decided to
investigate what happens to crystalline (Wyckoff structure) and amorphous Bi
when pressures below the atmospheric are applied (expansion). Here we show that
when expanded, \textit{c}-Bi becomes more metallic, since the eDoS increases
when the volume increases for the Wyckoff structure, while the amorphous eDoS
decreases. If the crystalline structure is maintained its $T_c$ would rise
under expansion, whereas it would diminish for the \textit{a}-Bi. Expansion can
be obtained in the laboratory by chemically etching Bi-based alloys, a process
also known as dealloying, for example.
