Victoria Atkinson at Live Science:
The strength of metallic bonding — and, therefore, the melting point — also decreases from the top to the bottom of the periodic table, as the atoms get larger. But extrapolating from these established trends, mercury should still have a melting point of around 266 F (130 C), which would make it solid at room temperature.
So what causes this giant disparity?
Mercury’s liquid state results almost entirely from relativistic effects, said Peter Schwerdtfeger, a quantum physicist at Massey University in New Zealand. Toward the bottom of the periodic table, the electrons in the heaviest elements experience such strong attraction to the atomic nucleus that they move close to the speed of light. At this point, they no longer obey the laws of classical physics, and the resulting quantum phenomena — known as relativistic effects — lead to surprising physical properties. How these manifest depends on the element.
More here.
Enjoying the content on 3QD? Help keep us going by donating now.