Dragons hide at the edges of the map from known elements: atomic giants so delicate and so scarce that they challenge easy study.
One of these giants has finally abandoned at least some of its secrets, with the chemists managing to gather enough einsteini to concretize important details about the chemistry and the ability of the mysterious element to form bonds.
For most of the 70s, the isotopes of einsteinium have been frustratingly difficult to study. Either they are too difficult to manufacture or they have a half-life of less than a year, and what is created of little beauty begins to break like a sand castle at high tide.
The behavior of the element is assumed to follow the patterns of its less robust companions in the actinide series. That is clear. But because of its large size, the strange relativistic effects make it more difficult to predict how it will react in certain chemical processes.
Usually, this confusion is easily clarified simply by performing a series of experiments.
The Lawrence Berkeley National Laboratory, of the U.S. Department of Energy, has finally put together enough things to do so.
Better known as the Berkeley Lab, the famous institute is already responsible for discovering a significant chunk of the upper limits of the periodic table of elements.
A dozen of them were the work of nuclear physicist Albert Ghiorso, a lifelong Berkeley researcher whose first career saw him develop radiation detectors as part of the Manhattan Project.
In the early 1950s, Ghiorso detected faint traces of two as yet unidentified radioactive elements in the air dust collected by aircraft flying after the first large-scale test of a thermonuclear device.
One of these elements was later christened einsteinium, which was named after the head of the famous theorist of German origin.
With an atomic mass of 252 and containing a huge amount of 99 protons, it is not light. As with all transuranic elements (elements heavier than uranium), einsteinium requires serious physics to produce it.
There is no convenient source or stock for diving. Cooking a batch requires firing smaller relatives, such as the curio, with a lot of neutrons in a nuclear reactor and then having a lot of patience.
The early efforts of the 1960s produced enough for the naked eye to see, with a minimum weight of 10 nanograms. Subsequent attempts got a little better, though they mostly caused impure batches.
This time, the researchers found about 200 nanograms of the isotope Einstein E-254, framed as part of a complex with a carbon-based molecule called hydroxypyridinone.
Getting here was not easy, marked by the contamination of smaller elements and then by the inevitable impact of the halt of the medium pandemic, only what would threaten an experiment that depends on a decaying material fast.
“It’s a remarkable achievement that we were able to work with this small amount of material and do inorganic chemistry,” says researcher Rebecca Abergel.
“It’s significant because the more we understand its chemical behavior, the more we can apply this understanding to the development of new materials or new technologies, not necessarily just with einsteinium, but also with other actinides. And we can set trends in the periodic table . “
Subjecting its stack of chelated E-254 atoms to X-ray absorption tests and photophysical measurements revealed important details about the bonding distance of the element, while demonstrating displacement emission behaviors. of wavelength that were not seen in other actinides.
Einsteinium is right on the edge of what we can achieve using banking chemistry. Although larger elements exist, their growing circumference puts them out of reach of the current capacity of technology to create enough for analysis.
But the more we learn about heavy atoms like einsteinium, the greater the potential to find stairs to build giants that are actually somewhere on the map.
“Similar to the last elements discovered in the last ten years, such as Tennessee, which used a berkeli target, if you managed to isolate enough pure einsteini to do so, you could start looking for other elements and get closer to the (theorized) island. of stability, ”says Abergel.
This research was published in Nature.