Lawrencium

Lawrencium is a chemical element with symbol Lr and atomic number 103. It is a synthetic element—meaning it does not occur naturally in the earth—but is instead created in a laboratory by bombarding atoms with a particle accelerator. It is the final element of the actinide series (actinides), a group of heavy radioactive elements.

All isotopes of lawrencium are radioactive and short-lived; many decay within minutes or seconds. For this reason, the amounts produced have been measured in small numbers of atoms, and there is no industrial or common use for the element. Research on lawrencium has focused primarily on its chemical properties and the electronic structure of heavy elements.

Discovery and naming

The element is named after Ernest Lawrence, an American physicist associated with the development of the cyclotron, a circular device used to accelerate small objects. Its discovery is linked to an American team working at the Berkeley laboratory in California, as well as a Soviet team working at Dubna. For a long time there was dispute over who deserved credit for the discovery, until international chemical authorities settled on the name and symbol.

Chemical properties

Lawrencium is classified as a heavy actinide. Its most stable chemical state is +3, as with many actinides. The electronic structure of Lr has been a subject of debate, since relativistic effects—the influence of high-speed electrons orbiting a heavy nucleus—can alter the order of energy levels. Experiments measuring the ionization energy of Lr have been carried out using extremely small numbers of atoms.

Production and research

Lawrencium is produced by bombarding a heavy target such as americium, californium, or berkelium with accelerated light particles. The result is separated using rapid chemical equipment, because of the short half-life. Research aids in understanding the limits of the periodic table and how the heavy nucleus is arranged.