A team of researchers has delivered our best understanding yet of one of the least studied corners of the periodic table. As reported in the journal Nature, scientists have provided the first-ever measurement of the bond distance of Einsteinium.
Einsteinium is element 99 in the periodic table and is one of the synthetic elements. It doesn’t occur naturally, and can only be created by humans. Creating it is very complex – this is why it took 69 years for researchers to actually make such measurements.
Einsteinium is a member of the actinides, a group in the bottom row of the periodic table that includes elements such as Uranium and Plutonium. The team had less than 200 nanograms of the element to work with, but it was a good start to understand einsteinium. The bond distance provides important clues to how this element interacts chemically, and it appears that it is different from the expectation scientists had for the actinide series.
"There's not much known about einsteinium," co-lead author Dr Rebecca Abergel, from UC Berkeley's Nuclear Engineering department, said in a statement. "It's a remarkable achievement that we were able to work with this small amount of material and do inorganic chemistry. It's significant because the more we understand about its chemical behavior, the more we can apply this understanding for the development of new materials or new technologies, not necessarily just with einsteinium, but with the rest of the actinides too. And we can establish trends in the periodic table."
The sample came from the Oak Ridge National Laboratory's High Flux Isotope Reactor, one of the few places that can create this element. There, scientists bombarded curium (another actinide) with neutrons to create nuclear reactions leading to the production of einsteinium. The difficulty then was purifying it, as the process also produces californium. After that, the next step was creating a specific sample holder to study it.
If these hurdles weren’t already enough, the research was interrupted due to the COVID-19 pandemic. This is not ideal when working with radioactive elements, as they will decay over time. Einsteinium-254 was the isotope used in this study and has a half-life of 276 days. When the research was allowed to resume, most of the sample was gone.
"This whole paper is a long series of unfortunate events," Dr Abergel commented.
Despite the setbacks, the team has demonstrated that the last decade of advancement now allows more detailed studies of the elements at the edge of the periodic table. This knowledge might lead to new materials and new tech.
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