Even the periodic table must bow to the reality of war

THE chill of geopolitical winds can be felt in unexpected places. One such realm is the hunt for new chemical elements, which various countries have undertaken in a spirit of mutually supportive rivalry since the end of the Cold War.

Those alliances are now cooling thanks to Russia’s war in Ukraine, with one renowned institution, the Lawrence Berkeley National Laboratory in California, striking out alone.

The Berkeley laboratory, along with other American labs plus facilities in Germany and Japan, had previously worked alongside Russia’s Joint Institute for Nuclear Research (JINR), checking each other’s work and sharing credit for discoveries. Now, according to Chemistry World, sanctions have torpedoed the arrangement.

Yuri Oganessian, a leading JINR scientist and the only person currently alive to have an element named after him, confirmed this. Sanctions, he told me by e-mail, “completely exclude scientific co-operation with Russia” and, since the institute is on Russian territory – in Dubna, near Moscow – it has now been isolated.

The quest to extend the periodic table may have splintered due to conflict but the fascination at what lies beyond the 118 known elements remains very much alive, with several countries taking up the gauntlet. The drive to complete the table is surely as explicable as the compulsion by explorers and navigators to map the lands, seas and mountains of the physical world. It is unthinkable that the contours of the atomic world should remain uncharted.

An element is a substance made of one type of atom, and is distinguished by its unique atomic number, which is the number of protons in its nucleus. A hydrogen atom has one proton and therefore an atomic number of one. Broadly, only elements up to uranium, 92, can be found in nature; heavier elements require synthesis in a laboratory. This becomes ever more difficult because it means shunting lots of positively charged protons – which naturally repel each other – together.

Overcoming this natural barrier usually involves smashing different atoms together at carefully calibrated speeds in particle accelerators.

Oganesson, for example, was created by colliding atoms of californium (atomic number 98) and calcium (20). Over several years, the fleeting existence of only a handful of oganesson atoms was recorded. Elements 93 and over are called “heavy”; those 104 and over are called “superheavy”.

Now Darmstadt’s GSI Helmholtz Centre for Heavy Ion Research in Germany and Tokyo’s Riken Nishina Centre for Accelerator-based Science are preparing to search for 119. Both have excellent recent track records, commemorated respectively with darmstadtium (110) and nihonium (113, the first element to be discovered or created in Asia).

Meanwhile, Oganessian is pursuing 119 and 120 aided by a US$60 million accelerator upgrade – and believes both are achievable this decade. The Lawrence Berkeley National Laboratory plans to leapfrog to 120 next year by colliding titanium and californium atoms. 

These gambits feel a bit like the voyages that sought the Northwest Passage, the elusive sea route linking the Atlantic to the Pacific that changed shipping forever.

That is because oganesson completes the periodic table’s seventh row – and the next heaviest elements will start the eighth, rumoured to be a point at which conventional chemistry, including the table’s famed repeating pattern of properties, breaks down.

Instead of existing for mere seconds or less, these elements might inhabit an “island of nuclear stability” and linger for years. These prospective heavyweights are predicted to show peculiar behaviour related to relativity. It is this unknown chemistry of the “superheavies” that Oganessian, now 90, admits to finding most intriguing.

When I asked him how many more elements science could produce – one theory predicts a total of 172 elements – he replied that making such predictions was a “difficult and thankless task”. Rather, he said, we must keep looking.

With admiration, he cites Riken, whose researchers took many years to document the creation and decay of only three nihonium atoms. Their work unblocked the dam: Oganessian’s team took just six months to find and confirm 114, named flerovium. 

As this year’s Nobel Prize in Chemistry, awarded for quantum dots, shows, the most rarefied pursuits can end up being useful; these nanoparticles are now used in TVs, LED screens and to illuminate tumour tissue for surgeons. But exploration also matters for its own sake: if an unmapped land of exotic chemistry lies over the horizon, we must surely set sail.