The Periodic Table of Elements is a continuously expanding record of matter. Unlike naturally occurring elements, modern additions are entirely synthetic, created in highly specialized laboratories. These superheavy elements represent a challenging frontier in physics and chemistry, requiring immense energy and precision to produce even a single atom. The process of adding a new element can span decades, involving synthesis, verification, and formal recognition by international bodies.
The Identity of Element 113
The element first successfully synthesized in 2004 was Element 113, now officially known as Nihonium (Nh). This distinction belongs to a team of Japanese scientists at the RIKEN Nishina Center for Accelerator-Based Science, who were the first in Asia to earn the right to name a new element. The initial creation occurred on July 23, 2004, when researchers recorded a single, fleeting atom of the new element.
How Superheavy Elements Are Synthesized
Creating a superheavy element like Nihonium requires a delicate and powerful process called “cold fusion,” executed within a particle accelerator. The RIKEN team utilized their RIKEN Linear Accelerator (RILAC) to accelerate a beam of Zinc-70 (\(^{70}\text{Zn}\)) ions to approximately 10% of the speed of light. This high-speed projectile beam was then directed at a thin, stationary target made of Bismuth-209 (\(^{209}\text{Bi}\)). The goal was to achieve a head-on collision that would fuse the nuclei of the two elements, where the atomic numbers of the zinc (30) and bismuth (83) combine to equal 113.
The fusion event is exceedingly rare because the nuclei naturally repel each other due to their positive electrical charges. Most of the zinc ions pass through the target or simply bounce away without fusing. When a successful fusion occurs, the unstable superheavy nucleus of Nihonium-278 (\(^{278}\text{Nh}\)) is formed. This newly created atom is then separated from the unreacted material and transferred to a detector using a device called a Gas-filled Recoil Separator (GARIS). The detection is based not on the element itself, but on the precise, predictable chain of alpha particle decays that the atom immediately undergoes.
Placement and Fleeting Characteristics
Nihonium sits in the seventh row of the periodic table, placing it in Period 7 and Group 13 (the boron group), and is classified as a p-block transactinide element. Its position suggests that it should exhibit properties similar to its lighter congeners, such as Thallium and Indium, and is predicted to be a post-transition metal. However, the extreme effects of relativity on the inner electrons of such heavy atoms may cause its chemistry to deviate slightly from simple prediction. Scientists must rely on these theoretical models because the element is so unstable that it cannot be collected in bulk for direct study.
Nihonium is defined by its extreme instability, quantified by its very short half-life. The isotope initially synthesized, Nihonium-278, exists for less than a thousandth of a second before decaying. Even the most stable known isotope, Nihonium-286, has a half-life of only around 10 to 20 seconds. This rapid decay through alpha emission means that the element transforms into a sequence of lighter, also-radioactive daughter elements. Observing this specific decay chain is the only way researchers can confirm the element’s momentary existence and its atomic identity.
The Long Road to Official Naming
The synthesis in 2004 was only the first step in a lengthy administrative process governed by the International Union of Pure and Applied Chemistry (IUPAC). For a discovery to be fully recognized, the evidence must be deemed conclusive. The RIKEN team provided additional, confirming synthesis events in 2005 and 2012 to strengthen their claim. This evidence was necessary to firmly anchor the decay chain of Nihonium-278 to previously known, lighter nuclides, providing unambiguous proof of its atomic number.
The IUPAC/IUPAP Joint Working Party formally recognized the RIKEN team’s priority for the discovery in December 2015, over a decade after the first event. This recognition granted the team the right to propose a permanent name and symbol for Element 113. The researchers proposed the name Nihonium (Nh), a direct reference to Nihon, the Japanese word for Japan, meaning “the Land of the Rising Sun.” Following a period of public review, the name Nihonium and the symbol Nh were officially approved by IUPAC in November 2016, securing the element’s place on the periodic table.