Without Ernest Lawrence, half the periodic table might never have been filled. He invented the cyclotron — the accelerator used to discover dozens of new elements. Lawrencium, element 103, is named in his honor. And rightly so: without his machine, many actinides would still be unknown.
Lawrencium is the last element in the actinide series. It sits at the boundary between two great families of elements. Its electron configuration is anomalous: instead of the expected 6d electron, a 7p electron appears. This is a consequence of relativistic effects — electrons move so fast that they change their behavior.
Lawrencium was first synthesized in 1961 at Berkeley by bombarding californium with boron ions. Only a few atoms were produced. Its most stable isotope, Lr-266, survives just 11 hours. Lawrencium is interesting as a 'transitional' element: it closes the actinide row and opens the door to the transactinides — superheavy elements of the fourth generation.
Lawrencium is extremely radioactive. It emits alpha particles, and some isotopes undergo spontaneous fission. Its most stable isotope survives only 11 hours. Scientists work with individual atoms, so the practical hazard is minimal. Only a handful of research centers worldwide are capable of synthesizing lawrencium.
Ernest Lawrence invented the cyclotron in 1930. This machine enabled the discovery of dozens of new elements and earned him a Nobel Prize.
Lawrencium is the last actinide. It closes a row of 15 elements and sits at the threshold of the transactinides — an entirely new class of elements.
Lawrencium's electron configuration is anomalous: [Rn]5f¹⁴7s²7p¹ instead of the expected 6d¹. Electrons break the rules because of Einstein's theory of relativity.
American and Soviet scientists at Dubna both competed for the discovery of lawrencium. The priority dispute lasted throughout the 1960s.
The most stable isotope, Lr-266, survives for only 11 hours. Within that window, scientists must create, isolate, and study the atoms.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
262Lr☢ | 262.109630 | synthetic | 3.6 hours | EC/α |
266Lr☢ | 266.119830 | synthetic | 11 hours | SF |
Cyclotron bombardment of californium