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What is Nihonium

Nihonium (pronunciation nee-hone-ee-em [2]), represented by the chemical symbol Nh, is a synthetic, radioactive, transuranium metal [1, 10, 11]. Of its two known isotopes, Nh 284 and Nh 286 [1], the latter is more stable with a half-life of 20 seconds [2].

Where Is It Found

The super heavy element cannot be found naturally on earth. A tiny amount has been synthesized in labs [1, 3].



Origin of Its Name: It is named after the Japanese name for Japan [1].

Who Discovered It: Scientists from The Institute of Physical and Chemical Research (RIKEN) in Japan [1].

How Was Nihonium Discovered

The first two atoms of the element were produced on July 23, 2004, at RIKEN by accelerating zinc ions to make them reach 10% of the speed of light and then allowing them to strike a bismuth target. The atoms were of nihonium 278 that quickly underwent alpha decay to dubnium 262 [2, 3].

Nihonium Identification

Atomic Number  113 [1]
CAS Number  54084-70-7 [1]
Position in the periodic table Group Period Block
  13 [1] 7 [1] p [1]

Properties and Characteristics of Nihonium

General Properties

Atomic mass 286 atomic mass units [1]
Atomic weight 286 [1]

Physical Properties

Color/appearance Unknown [4,5]
Melting point/freezing point Unknown [1]
Boiling point Unknown [1]
Density Unknown [1]
State of matter at room temperature (normal phase) Solid (estimated) [1,3]

Chemical Properties

Oxidation states Unknown [1]
Reactivity Unknown [8]

Atomic Data of Nihonium (Element 113)

Valence electrons 7s27p1 [9] (as predicted depending on its position in periodic table)
Electron configuration (noble gas configuration) [Rn] 5f146d107s27p1 [1]
Atomic structure
– Number of Electrons 113 [3]
– Number of Neutrons 113 [3]
– Number of Protons 173 [3]
Energy levels [3]
– First Energy Level 2
– Second Energy Level 8
– Third Energy Level 18
– Fourth Energy Level 32
– Fifth Energy Level 32
– Sixth Energy Level 18
– Seventh Energy Level 3
Radius of atom
– Atomic Radius Unknown [1]
– Covalent Radius 1.36 Å [1]
Electronegativity Unknown [1]
Ionization energy

(kJmol-1) [1]

1st 2nd 3rd 4th 5th 6th 7th

Nihonium Electron Configuration (Bohr Model)

Nihonium Uses

The minuscule amount of production of the metal restricts its use to research purposes only [1].

Is It Dangerous

The highly radioactive nature makes it potentially harmful [1, 3].

Interesting Facts

  • It was temporarily given the name ununtrium (symbol Uut [4]) representing its atomic number before being officially named by IUPAC on 28th November 2016 along with moscovium, tenessine and oganesson [6, 7].
  • The name Japonium was considered for the element by the researchers to emphasize the Japan connection, but the proposal was dismissed since the word Jap is insulting to the Japanese [12].

Nihonium (Ununtrium) Cost

Unknown as it is not available commercially [3].



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