Nihonium

Nihonium, ₁₁₃Nh

Nihonium
Pronunciation	/nɪˈhoʊniəm/ ​(nih-HOH-nee-əm)
Mass number	[286]
Nihonium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Tl ↑ Nh ↓ (Uhs) copernicium ← nihonium → flerovium
Atomic number (Z)	113
Group	group 13 (boron group)
Period	period 7
Block	p-block
Electron configuration	[Rn] 5f14 6d10 7s2 7p1 (predicted)[1]
Electrons per shell	2, 8, 18, 32, 32, 18, 3 (predicted)
Physical properties
Phase at STP	solid (predicted)[1][2][3]
Melting point	700 K ​(430 °C, ​810 °F) (predicted)[1]
Boiling point	1430 K ​(1130 °C, ​2070 °F) (predicted)[1][4]
Density (near r.t.)	16 g/cm3 (predicted)[4]
Heat of fusion	7.61 kJ/mol (extrapolated)[3]
Heat of vaporisation	130 kJ/mol (predicted)[2][4]
Atomic properties
Oxidation states	(−1), (+1), (+3), (+5) (predicted)[1][4][5]
Ionisation energies	1st: 704.9 kJ/mol (predicted)[1] 2nd: 2240 kJ/mol (predicted)[4] 3rd: 3020 kJ/mol (predicted)[4] (more)
Atomic radius	empirical: 170 pm (predicted)[1]
Covalent radius	172–180 pm (extrapolated)[3]
Other properties
Natural occurrence	synthetic
Crystal structure	​hexagonal close-packed (hcp) (predicted)[6][7]
CAS Number	54084-70-7
History
Naming	After Japan (Nihon in Japanese)
Discovery	Riken (Japan, first undisputed claim 2004) JINR (Russia) and Livermore (US, first announcement 2003)
Isotopes of nihonium v e
Main isotopes[8] Decay abun­dance half-life (t1/2) mode pro­duct 278Nh synth 0.002 s α 274Rg 282Nh synth 0.061 s α 278Rg 283Nh synth 0.123 s α 279Rg 284Nh synth 0.90 s α 280Rg ε 284Cn 285Nh synth 2.1 s α 281Rg SF – 286Nh synth 9.5 s α 282Rg 287Nh synth 5.5 s?[9] α 283Rg 290Nh synth 2 s?[10] α 286Rg
Category: Nihonium view talk edit | references

Nihonium is a synthetic chemical element; it has symbol Nh and atomic number 113. It is extremely radioactive: its most stable known isotope, nihonium-286, has a half-life of about 10 seconds. In the periodic table, nihonium is a transactinide element in the p-block. It is a member of period 7 and group 13.

Nihonium was first reported to have been created in 2003 by a Russian–American collaboration at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, and in 2004 by a team of Japanese scientists at Riken in Wakō, Japan. The confirmation of their claims in the ensuing years involved independent teams of scientists working in the United States, Germany, Sweden, and China, as well as the original claimants in Russia and Japan. In 2015, the IUPAC/IUPAP Joint Working Party recognised the element and assigned the priority of the discovery and naming rights for the element to Riken.^[11] The Riken team suggested the name nihonium in 2016, which was approved in the same year. The name comes from the common Japanese name for Japan (日本, nihon).

Very little is known about nihonium, as it has only been made in very small amounts that decay within seconds. The anomalously long lives of some superheavy nuclides, including some nihonium isotopes, are explained by the "island of stability" theory. Experiments support the theory, with the half-lives of the confirmed nihonium isotopes increasing from milliseconds to seconds as neutrons are added and the island is approached. Nihonium has been calculated to have similar properties to its homologues boron, aluminium, gallium, indium, and thallium. All but boron are post-transition metals, and nihonium is expected to be a post-transition metal as well. It should also show several major differences from them; for example, nihonium should be more stable in the +1 oxidation state than the +3 state, like thallium, but in the +1 state nihonium should behave more like silver and astatine than thallium. Preliminary experiments in 2017 showed that elemental nihonium is not very volatile; its chemistry remains largely unexplored.