Superconductors are elements whose electrical resistance becomes practically zero when falling below the so-called transition tempperature. Technical applications of superconductivity are the generation of strong magnetic fields as well as measurement and energy technology.

without transition tempperature

Elements have no (known) transition tempperature. Examples are hydrogen and other elements of the 1st main group, all noble gases as well as many elements of the lanthanides and actinides.

with transition tempperature under special conditions

Superconducting properties are only achieved in these elements under certain conditions, such as high pressure or when the element is present as a thin film.

with transition tempperature (solid body, normal pressure)

Elements have a transition tempperature under standard conditions (as a solid body and under normal pressure). Examples are many subgroup elements, aluminum, tin and lead.