Definition of superheavy in US English:



  • Relating to or denoting an element with an atomic mass or atomic number greater than those of the naturally occurring elements, especially one belonging to a group above atomic number 110 having proton/neutron ratios which in theory confer relatively long half-lives.

    • ‘These superheavy elements do not exist naturally on earth; they may be generated by supernova explosions in stars, or by fusions during the dawn of the universe.’
    • ‘Because of strong electrostatic repulsion, some of these superheavy nuclei may have extremely short lifetimes.’
    • ‘We have found a steep rise in the stability of superheavy nuclei with atomic number, but we are still far from the region in which nuclei may live for thousands, maybe even millions, of years.’
    • ‘Since the 1960s, nuclear chemists have theorized that superheavy elements with life-times of hours, days, or even longer are possible.’
    • ‘But in fact the result was a surprise, because the chemical behaviour of the preceding superheavy elements 104 and 105 is distorted by the effects of relativity on the electrons surrounding the immense nuclei.’