Livermorium (Lv)

Element 116 was made in Russia. The beam was Russian, the accelerator was Russian, the target chamber and the detectors were at Dubna, and the atoms — such as they were — existed there and nowhere else. The element is named after a laboratory in California.

That is not a scandal, but it is worth explaining, because the naming of livermorium is the clearest illustration of what a modern superheavy-element collaboration actually consists of.

What the American half contributed

Three ingredients are needed to make element 116, and only one of them is a beam.

• The target. Element 116 requires curium-248, an isotope produced by years of neutron irradiation at Oak Ridge and separated afterwards from a mixture of actinides in a shielded facility. There are very few places on Earth that can supply it, and Dubna is not one of them.
• The analysis. Identifying a handful of decay chains in a dataset dominated by background requires statistical methods that determine whether a claimed sequence could have arisen by chance. Lawrence Livermore's group specialised in exactly this, and their independent scrutiny of the raw data was a substantial part of what made the claims credible.
• The accelerator. Dubna's, running a calcium-48 beam for months at a time.

The July 2000 experiment produced a decay chain assigned to livermorium-292. The IUPAC and IUPAP joint working party accepted the discovery in June 2011, crediting the Dubna and Livermore collaboration jointly.

A separate claim on element 116 had been made and withdrawn a decade earlier. A 1999 report from Berkeley described a 116 isotope observed as the daughter of a heavier element; the paper was retracted after the data underlying it were found to be fabricated.

A runaway sailor

Livermore, California is named after Robert Livermore, an Englishman who left his ship on the Californian coast in the 1820s, became a naturalised Mexican citizen, married into a local family and ran cattle on a land grant in the valley that now carries his name. The town grew around the ranch; the national laboratory was established there in 1952; and element 116 is named after the laboratory.

The chain of naming therefore runs from a nineteenth-century deserter to a square on the periodic table, which is a longer and stranger provenance than most element names can manage.

There was very nearly a different name. The Dubna team's first choice for element 116 was moscovium, after their own region. When the square was assigned to Livermore instead, the name was set aside and used a year later for element 115. Livermorium and its symbol Lv became official on 23 May 2012.

Milliseconds

The isotopes of element 116 are among the shortest-lived of any named element. Livermorium-293 survives on the order of fifty milliseconds; livermorium-290 rather under ten. Nothing about the element can be studied by chemical means, because there is no chemical operation that completes in fifty milliseconds and no way to accumulate more than one atom at a time.

What the isotopes are good for is making other things. Livermorium decays by alpha emission to flerovium, so a livermorium synthesis is also a flerovium factory, and several of the atoms used in the chemical studies of element 114 arrived that way rather than being produced directly. In this region of the table, elements are frequently investigated as somebody else's decay products.

What group 16 predicts, and what it does not know

Livermorium sits below polonium in group 16, the chalcogens, and the predictions about it should be read strictly as predictions — no measurement of any chemical property of element 116 exists.

Relativistic calculations expect the +2 state to dominate, with +4 much less accessible than it is for polonium, because the 7p₁/₂ electrons are stabilised and effectively withdrawn from bonding. The same reasoning suggests element 116 would be a metal rather than a metalloid, with a melting point somewhere in the region of 700 K, and that a hydride analogous to hydrogen sulfide would be unstable. These are computed numbers with no experimental anchor whatever. Element 114 at least has measurements to check its predictions against; element 116 has none, and no realistic experiment on the horizon could supply any.