Nihonium

Nihonium is a synthetic chemical element with the symbol Nh and the atomic number 113. Because it is synthetic, it does not exist naturally in the world. Instead, scientists must create it using massive machines in specialized laboratories. It is classified as a transactinide element located in the p-block of the periodic table. Specifically, it belongs to period 7 and group 13. This placement suggests it shares certain characteristics with other elements in its group.

Scientists use two main methods to create superheavy elements like nihonium: hot fusion and cold fusion. In hot fusion, researchers bombard a heavy actinide target with lighter ions. For example, the Joint Institute for Nuclear Research (JINR) used a target of americium-243 and bombarded it with calcium-48 projectiles. This reaction produced element 115, which then underwent alpha decay to create nihonium. In contrast, cold fusion uses different targets, such as bismuth-209, bombarded with zinc-70 ions. This method was used by the Riken team in Japan to produce the isotope nihonium-278.

Nihonium is extremely radioactive and unstable. Its most stable known isotope is nihonium-286, which has a half-life of only about 10 seconds. This means the atoms decay very quickly after they are made. However, some scientists study the "island of stability" theory to explain why some superheavy nuclides live longer than others. This theory suggests that certain combinations of protons and neutrons can create more stable atoms. Experiments show that as more neutrons are added to nihonium isotopes, their half-lives increase from milliseconds to several seconds.

The discovery of nihonium involved a long history of international scientific collaboration. Between July 14 and August 10, 2003, a Russian-American team at JINR in Dubna, Russia, reported the first creation of the element. They worked with the Lawrence Livermore National Laboratory in California. Later, on July 23, 2004, a Japanese team at Riken in Wakō, Japan, led by Kōsuke Morita, reported their own successful synthesis.

Confirming a new element is a rigorous process that takes many years. The IUPAC/IUPAP Joint Working Party must examine all claims to ensure the atomic number is truly new. To prove a discovery, scientists often use "anchoring," which means tracing the decay chain back to a known element. The Riken team achieved this by showing their nihonium-278 decayed into bohrium-266, an element already discovered in 2000. Other teams in the United States, Germany, Sweden, and China also performed independent work to verify these results.

In 2015, the Joint Working Party officially recognized the element and assigned naming rights to the Riken team. In 2016, the name "nihonium" was approved. The name is derived from "Nihon," which is the common Japanese name for Japan. This honors the Japanese scientists who provided the definitive confirmation of the element. The discovery was significant because it filled a gap in the periodic table for odd-numbered elements.

While very little is known about its physical appearance, scientists can predict its chemical behavior. Nihonium is expected to be a post-transition metal. It is predicted to have similar properties to its group members: boron, aluminium, gallium, indium, and thallium. However, it may show unique differences. For instance, nihonium should be more stable in a +1 oxidation state than a +3 state. In this +1 state, it might behave more like silver or astatine than its relative thallium. Preliminary experiments suggest that elemental nihonium is not very volatile and is less reactive than thallium.