Closo pentastannide dianion
= Closo pentastannide dianion
{title2=$\mathrm{Sn_5^{2-}}$}
$\mathrm{Sn_5^{2-}}$, a five-vertex trigonal-bipyramidal <Zintl cluster>. Removing five mainly s-rich <lone pairs> from its 22 <valence electrons> leaves 12 skeletal electrons.