Completing the Seventh Row

In December 2015, IUPAC officially recognized four new elements discovered by Japanese, Russian, and American researchers, completing the periodic table’s seventh row: Nihonium (Nh, 113), Moscovium (Mc, 115), Tennessine (Ts, 117), and Oganesson (Og, 118). These superheavy synthetic elements exist for mere milliseconds before decaying, created by smashing lighter atoms together in particle accelerators.

How Superheavy Elements Are Made

Creating element 118 (Oganesson) required bombarding californium-249 targets with calcium-48 ions accelerated to 10% light speed in cyclotrons. Over months, four atoms of Oganesson were created, each existing for ~0.7 milliseconds before decaying into lighter elements. The difficulty increases exponentially: element 118 required trillion-trillion collisions to produce a handful of atoms. Synthesizing element 119 or 120 may require years of beam time with no guaranteed success.

The Island of Stability Quest

Nuclear physics predicts an “island of stability”—theoretical superheavy elements (around atomic numbers 114-126) with relatively long half-lives (seconds to days vs. microseconds) due to “magic numbers” of protons/neutrons creating stable nuclear configurations. Oganesson sits near this island, but whether truly stable isotopes exist remains unknown. Discovering long-lived superheavy elements could reveal new chemistry and materials with impossible-on-Earth properties.

Naming Rights & Nationalism

Discovering elements earns naming rights, becoming scientific immortality and national pride. Nihonium (Japan, first Asian-discovered element) honored Japan. Moscovium honored Moscow. Tennessine honored Tennessee (Oak Ridge National Lab). Oganesson honored Yuri Oganessian, the only living person with an element named after them (at the time). The politics of element naming reflect Cold War legacies (Russian-American collaboration), regional pride, and chemistry’s international culture.

Sources:

• IUPAC announcement: https://iupac.org/iupac-announces-the-names-of-the-elements-113-115-117-and-118/
• Science superheavy elements:
• Physical Review Letters Og synthesis: http://web.archive.org/web/20250716005935/https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.104.142502