Making Advances in Synthesizing Molecular Compounds with Heavy Elements

Lawrence Livermore National Laboratory (LLNL) researchers have recently developed a groundbreaking technique that allows for the synthesis of molecular compounds containing heavy elements, such as americium and curium, in a more efficient and streamlined manner. This new pathway has the potential to revolutionize the field of radioactive element chemistry, enabling scientists to conduct serial chemistry with radioactive elements. This advancement could significantly accelerate research and development efforts related to nuclear waste management and radiopharmaceuticals.

In a series of articles published in Chemical Communications and the JACS Au, LLNL scientists discuss how this novel technique has paved the way for the creation of a wide array of new compounds, including the first trivalent americium polyoxometalate compound and two new compounds containing curium. Curium, in particular, has been a challenging element to study, with only a handful of crystal structures reported since its discovery in 1944. However, LLNL researchers have managed to discover five new crystal structures of curium molecular compounds in just the past two years.

Ian Colliard, a postdoctoral researcher at LLNL and co-author of the papers, emphasized the significance of this new chemical platform in enabling the synthesis and study of compounds containing a variety of actinides. By utilizing significantly less material (micrograms versus milligrams), researchers can not only accelerate the rate of compound creation but also reduce costs associated with these experiments, benefiting the Department of Energy.

Challenges in Actinide Chemistry

Actinides, which include heavy elements beyond plutonium, pose unique challenges for chemists due to their limited availability, high radioactivity, and toxicity. Unlike more traditional elements like iron or copper, actinides such as curium and americium are scarce and expensive to obtain, with just a few milligrams available per year. These constraints, coupled with stringent regulatory requirements for handling nuclear materials, have hindered advancements in actinide chemistry.

The development of this new chemical platform offers a promising solution to these challenges, providing researchers with the tools needed to delve deeper into the intricacies of actinide chemistry. By unlocking new properties and compounds specific to actinides, scientists can explore a wide range of applications, from chemical separations to the development of novel radiopharmaceutical drugs and improvements in nuclear waste management.

One of the key findings of the LLNL research is the revelation that actinide chemistry differs significantly from lanthanide chemistry, dispelling the notion that they behave similarly. Historically, researchers have used lanthanide surrogates to conduct experiments on actinides, assuming that the two groups of elements would exhibit comparable behavior. However, through their innovative chemical system, LLNL scientists were able to demonstrate that actinides form unique structures that have not been observed in lanthanides.

By synthesizing and characterizing a complete series of compounds containing both actinides and lanthanides, researchers were able to uncover the distinct short-range and long-range organizational differences between the two groups. This unexpected discovery highlights the importance of understanding the unique properties of actinides and challenges the conventional wisdom that actinide chemistry can be predicted based on lanthanide chemistry alone.

The development of this new technique marks a significant milestone in the field of actinide chemistry, offering researchers an unprecedented opportunity to explore the complex properties of heavy elements and expand the horizons of scientific discovery. Through continued research and innovation, scientists can unlock new insights into the behavior of actinides, paving the way for advancements in various industries, including nuclear technology, healthcare, and environmental science.