Beryllium dimer
= Beryllium dimer
{title2=$\mathrm{Be_2}$}
The neutral molecule Be-two. Its simplest filled sigma-two-s/bonding and antibonding description gives zero <bond order>, but mixing of accessible two-p configurations and <electron correlation> produce a weak <covalent bond>. Resolved vibrational levels establish a bound ground-state potential.<Beryllium dimer caught in the act of bonding by Jeremy M. Merritt and colleagues>{ref}