Isotope …, "m" are the atomic masses of each individual isotope, and "x", …, "x" are the relative abundances of these isotopes. Several applications exist that capitalize on properties of the various isotopes of a given element. Isotope separation is a significant technological challenge, particularly with heavy elements such as uranium or plutonium. Lighter elements such as lithium, carbon, nitrogen, and oxygen are commonly separated by gas diffusion of their compounds such as CO and NO. The separation of hydrogen and deuterium is unusual because it is based on chemical rather than physical properties, for example in the Girdler sulfide process.
Isotopes of rutherfordium Isotopes of rutherfordium Rutherfordium (Rf) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was either Rf in 1966 or Rf in 1969. There are 16 known radioisotopes from Rf to Rf (3 of which, Rf, Rf, and Rf are unconfirmed) and 4 isomers. The longest-lived isotope is Rf with an estimated half-life of 5 hours. The longest directly measured half-life is Rf at 11 minutes, and the longest-lived isomer is Rf with a half-life of 81 seconds. Super-heavy elements such