Scientists Uncover the Secrets of an 80-Year-Old Rare-Earth Element

Scientists have made a groundbreaking discovery, unraveling the mysteries of the rare Earth mineral Promethium, which had previously eluded researchers for the past 80 years since its discovery.

The Periodic Table of Elements stands as a testimony to the strides scientists and researchers have made in understanding the chemical composition of our world.

Published in Nature, the study’s findings fill a massive gap in chemistry textbooks, and could eventually lead to better methods for separating promethium from similar elements in nuclear waste.

Researchers estimate that less than 1 kilogram of promethium currently exists in the Earth’s crust, and scientists have previously harnessed its radiation to power pacemakers and spacecraft.

Promethium was first discovered back in 1945 and was placed into the lanthanide elemental category, which comprises 15 metallic chemicals often dubbed rare earth metals.

Despite promethium’s mysterious nature, scientists were able to determine some of its properties, including strong magnetism, which allowed them to use the element in several modern products, including atomic batteries and smartphones.

The study of Promethium has presented formidable challenges, primarily due to its inherently unstable and radioactive nature. This characteristic often leads to its transformation into other elements before researchers can conduct thorough examinations.

Scientists working at the Oak Ridge National Laboratory, which coincidentally is the precursor to the original lab that discovered Promethium, implemented a new process that permitted them to create an isotope of Promethium called Promethium-147.

“The whole idea was to explore this very rare element to gain new knowledge,” said Alex Ivanov, an ORNL scientist who co-led the research, (via Phys).

For the first time, scientists were able to conduct tests of the bonding properties of Promethium using X-ray spectroscopy, and the results of their work were shared in the journal Nature.

“There are thousands of publications on lanthanides’ chemistry without promethium. That was a glaring gap for all of science,” said ORNL’s Santa Jansone-Popova, who co-led the study.

The ORNL-led team of scientists kicked off the research by preparing a chemical complex of promethium, which allowed the element to show off its characterization in solution for the first time.

The study details how the researchers bombarded the promethium using a highly technical process that utilized high-energy photons enhanced by a particle accelerator.

According to Scientific American, current separation methods that often use molecules bind positively charged lanthanide ions in solution, forming coordination complexes.

Essentially, the experiment’s results allowed researchers to compare promethium’s properties with those of other rare earth metals for the first time since its discovery.

According to the study’s co-author, the analysis of promethium will allow researchers to better understand rare Earth metals as a whole.

The team provided the first demonstration of a lanthanide contraction feature, which showed that the radii of their ions decrease as the atomic numbers increase. This contraction creates chemical and electronic properties by confining the same charge to a shrinking space.

The team also performed quantum chemical calculations and molecular dynamics simulations at the Oak Ridge Leadership Computing Facility using the only supercomputer capable of calculating computational resources.

“It’s really astonishing from a scientific viewpoint. I was struck once we had all the data,” said Ivanov. “The contraction of this chemical bond accelerates along this atomic series, but after promethium, it considerably slows down.”

With the newfound ability to study the bonding properties of Promethium, researchers from ORNL may be able to produce larger quantities of this rare metal, which could potentially revolutionize the production of modern devices.

“You cannot utilize all these lanthanides as a mixture in modern advanced technologies because first, you need to separate them,” said Santa Jansone-Popova,

We know very little about a handful of elements on the periodic table beyond their existence. Scientists have largely identified Element 120, or Unbinilium, as a “hypothetical chemical element,” which, once discovered, will be the heaviest element on the planet.

Hiromitsu Haba, who leads the Superheavy Element Research Group at RIKEN Nishima Center for Accelerator-based Science in Saitama, Japan said, “The search for the superheavy elements beyond 118, oganesson, is proving to be a great challenge.”

Jacklyn Gates, a nuclear scientist at the California lab who is leading the effort, said, “We had never demonstrated this reaction before, and proving it was possible was essential before we embarked on our attempt to make 120.”