How Do They Name New Elements?

You can name them for mythical creatures, but you can’t name one after your mom.

Over the weekend, a team of Russian and American scientists announced that they had very briefly created two new chemical elements, ununtrium and ununpentium. How did they come up with those names?

Actually, they’re only temporary. Scientists who synthesize new elements are allowed to recommend permanent names for their creations—but only after the body that actually assigns names, the International Union of Pure and Applied Chemistry, can verify that the researchers in question really created the element, a process that can take years. Until then, the IUPAC recommends that scientists use an awkward naming convention based on the atomic numbers of the new elements. Each digit of the element’s atomic number, say 115, is assigned a Latin root—like un for 1 or pent for 5. By adding an elemental -ium at the end of the word, scientists arrive at the temporary name: in this case, ununpentium.

This naming convention was first published in 1990 to help prevent future controversies like the one that was then engulfing the scientific community, which couldn’t decide how to name the transfermium elements—super-heavies with atomic numbers above 100. For decades Russians, Americans, and Germans had been fighting over who first discovered some of these elements and several names were floating around. Element 104, for example, was known as rutherfordium in American labs (after New Zealand physicist Ernest Rutherford) and kurchatovium in Russian ones (after Soviet physicist Igor Kurchatov). The IUPAC proposed a slate of compromise names in 1994, but it wasn’t until 1997 that the IUPAC Council—the governing body that includes representatives from all IUPAC’s member countries, and serves as a kind of Security Council of inorganic chemistry—voted to accept a brokered agreement splitting up the elements among the three camps.

These days, the naming process can still invite controversy. Before scientists are invited to suggest a permanent name for a new element, the IUPAC convenes a “Joint Working Group” with the International Union of Pure and Applied Physics to confirm that it was actually created. Since new elements are usually very unstable and last only fractions of a second before decaying, the review process is not a rubber stamp. In 1999, researchers at the Berkeley Lab in California published claims that they had created Elements 116 and 118. But when the IUPAC-IUPAP working group was unable to confirm the results of their experiment, Berkeley was forced to withdraw its claim. One scientist was later fired for forging the data.

Once the working group confirms the creation of a new element, it invites the scientists who published the first verifiable results on the subject to recommend a name that follows certain guidelines: “Elements can be named after a mythological concept, a mineral, a place or country, a property, or a scientist.” In addition, for the sake of “linguistic consistency,” names of all new elements must end in -ium. The IUPAC then publishes the proposed name and invites public comment for five months. After responding to all relevant comments (last time a name was published, some respondents apparently took issue with the grammar of the press release, rather than the proposed name for Element 110, darmstadtium), the committee recommends the name to the IUPAC Council, which votes on whether to accept it at its next meeting.

Don’t expect ununtrium or ununpentium to be confirmed or get official names anytime soon. Even though scientists in Darmstadt, Germany, created Element 111—the most recent IUPAC-IUPAP-confirmed element—almost 10 years ago, there’s still no permanent replacement for its provisional moniker, unununium. The Germans, who named their last find darmstadtium after their hometown, have yet to propose a name.

Next question?

Explainer thanks Dr. John W. Jost, executive director of IUPAC.