# Why does mercury have low melting and boiling points?

Many metals have relatively high melting and boiling points, but mercury has relatively low melting and boiling points. What are the possible reasons for this?

Mercury is different! It is not as reactive as its neighbors in the Periodic Table, it doesn't conduct heat and electricity as well as other metals, and it is a liquid unlike other metals. The electronic structure of mercury is $\ce{[Xe] 5d^{10} 6s^2}$, so the first thing we notice is that all of its orbitals are full, there are no unpaired electrons in mercury. This helps explain mercury's reluctance to react with other materials or form bonds with other mercury atoms. Most metal atoms share their outer electrons with other metal atoms, in fact, all of these "shared" metal electrons exist as a diffuse "sea" of electrons. It is the extended nature of this sharing that makes metals good conductors of heat and electricity. The fact that the metal electrons are shared provides a strong bonding interaction between metal atoms that gives metals their solid structure. None of this applies to mercury. With its filled shell electron configuration it is very reluctant to form bonds even with other mercury atoms.