Earlier this year, the International Union of Pure and Applied Chemistry (IUPAC) accepted the evidence that indicated we had produced four new elements, filling out the bottom row of the periodic table. At the time, they were given temporary names—and catchy ones, too. We'll all be sad to see ununseptium (element 117) go, but you'll be glad to know that the formal names are probably just as difficult to pronounce properly.

Further Reading Standards organization accepts completion of last row of periodic table

Three of the new names honor the places where the elements were produced; the fourth recognizes a key person who helped organize the work involved.

For element 113, Japan is recognized by one of its alternate names, Nihon. The element will be called nihonium, and bear the symbol Nh. The remaining elements were produced by collaboration between the Joint Institute for Nuclear Research in Russia and two of the US' national labs: Oak Ridge and Lawrence Livermore. Element 115 honors the Russian part of that collaboration with the name moscovium (symbol Mc). 117 handles Oak Ridge by getting the name tennessine, or Ts. Lawrence Livermore has the misfortune of being in California, which already has an element named after it, so it gets left out.

That leaves element 118, which is named after Yuri Oganessian, a key figure in the research on these ultra-heavy elements. In elemental terms, his name leads to oganesson, or Og.

The committee involved in this approval notes that Ts, the new symbol for tennessine, is also used as an abbreviation for a chemical group called tosyl. But frankly, it doesn't care ("this is not considered to be a valid objection," write the authors who represent the IUPAC). As the elements' names have been approved by all the relevant parties and the period for public comments is over, fans of tosyl groups are out of luck.