In his seminal essays on “Molecular Beauty,” Nobel laureate Roald Hoffmann described the qualities that make certain molecules beloved by chemists. He organized their virtues into categories including shape and utility. Some molecules he called “frogs about to be kissed.”
Berkelocene, a novel compound recently synthesized at Lawrence Berkeley National Laboratory, is one such molecule.
Berkelocene contains berkelium (atomic symbol: Bk), a radioactive element discovered in the same facility in 1949. Berkelium belongs to the actinides—heavy, unstable elements that exist mostly as nuclear waste. In berkelocene, a berkelium atom is pinned between two carbon rings. Because heavier actinides are quick to decay, berkelocene may be the heaviest possible actinide-carbon sandwich compound.
As such, berkelocene has utility. Since most actinides are too rare or short-lived to handle directly, berkelocene serves as a stand-in, one that could help scientists better understand—and eventually manage—the complex chemistry of nuclear waste.
Symmetry is another source of berkelocene’s appeal. The molecular beauty Hoffmann describes is less about visuals and more about possibility. Scientists use symmetry to understand underlying rules of matter. The same electromagnetic forces that shape a snowflake also govern galaxies. Studying berkelocene helps chemists understand those rules at the quantum level.
While no one’s about to kiss this highly radioactive molecule, researchers hope that studying it may unlock secrets about an entire class of elements. That makes berkelocene a promising tool to explore some of the most challenging and consequential parts of the periodic table.
