Nihonium (113) *UPDATED!*

Nihonium: the essentials

Nihonium is the name of a chemical element with the symbol of Nh and was formerly known as Ununtrium, with the temporary symbol Uut and atomic number 113. The element was named for Japan, as it was first discovered at RIKEN in Japan in 2004.
It was known as eka-thallium or simply element 113, is an extremely radioactive synthetic element (an element that can be created in a laboratory but is not found in nature); the most stable known isotope, ununtrium-286, has a half-life of 20 seconds. Ununtrium was first created in 2003 by the Joint Institute for Nuclear Research in Dubna, Russia, with collaboration with scientists at the Lawrence Livermore National Laboratory in Livermore, California.The claim for discovery has not yet been ratified, but the results are now published in a reputable peer-reviewed journal. Once the discovery is confirmed, then naming will commence.

Name: Nihonium Symbol: Nh Atomic number: 113 Atomic weight: [ 284 ] Standard state: presumably a solid at 298 K CAS Registry ID: 54084-70-7

Group in periodic table: 13 (boron group) Group name: (none) Period in periodic table: 7 Block in periodic table: p-block Color: unknown, but probably metallic and silvery white or grey in appearance Classification: Metallic

Historical information

Experimental results reported in 2004 involving the bombardment of americium-243 with calcium-48 ions are consistent with the formation in the laboratory of a few atoms of elements 113 and 115. In experiments conducted at the JINR U400 cyclotron with the Dubna gas-filled separator between July 14 and Aug. 10, 2003, atomic decay patterns were observed said to confirm the existence of element 115 and element 113. In these decay chains, element 113 is produced via the α-decay of element 115.

If you want to read more about the discovery of this element, the results are published in the 1 February 2004 issue of Physical Review C: "Experiments on the synthesis of element 115 in the reaction ²⁴³Am(⁴⁸Ca,xn)^21–x115", Yu. Ts. Oganessian, V. K. Utyonkoy, Yu. V. Lobanov, F. Sh. Abdullin, A. N. Polyakov, I. V. Shirokovsky, Yu. S. Tsyganov, G. G. Gulbekian, S. L. Bogomolov, A. N. Mezentsev, S. Iliev, V. G. Subbotin, A. M. Sukhov, A. A. Voinov, G. V. Buklanov, K. Subotic, V. I. Zagrebaev, M. G. Itkis, J. B. Patin, K. J. Moody, J. F. Wild, M. A. Stoyer, N. J. Stoyer, D. A. Shaughnessy, J. M. Kenneally, and R. W. Lougheed, Phys. Rev. C, 2004, 69, 021601(R).

Physical properties

• Melting point: 700 K, 430 C, 810 F
• Boiling point: 1430 K, 1130 C, 2070 F
• Density of solid: 16000 (predicted) kg m^-3
• Heat of Fusion:  7.61kJ mol^-1

Orbital properties

• Ground state electron configuration:  [Rn].5f¹⁴.6d¹⁰.7s².7p¹
• Shell structure:  2.8.18.32.32.18.3
• Term symbol:   ²P_1/2 (a guess based upon guessed electronic structure)
• Pauling electronegativity: no data (Pauling units)
•  First ionization energy: 704.9 kJ mol^-1
•  Second ionization energy: 2240 kJ mol^-1
• Third ionization energy: 3020 kJ mol^-1

Isolation

Currently, the identification of element 113 is yet to be confirmed by IUPAC, but the experiments leading to element 113 are now published in a prestigious peer reviewed journal. As only about four atoms of element 113 has ever been made (through decomposition of element 115 nuclei made in nuclear reactions involving fusing calcium nuclei with americium nuclei) isolation of an observable quantity has never been achieved, and may well never be. In the experiments leading to element 115 the following reactions occurred

²⁴³₉₅Am + ⁴⁸₂₀Ca → ²⁸⁷₁₁₅Uup + 4 ¹n

²⁴³₉₅Am + ⁴⁸₂₀Ca → ²⁸⁸₁₁₅Uup + 3 ¹n

In these first experiments, three nuclei of the ^288Nh isotope were made and one of the ²⁸⁷Nh isotope. All the nuclei formed decayed in less than a second by emitting α-particles. These decays resulted in isotopes of ununtrium, element 113, (mass number 283 or 284, containing 113 protons and either 170 or 171 neutrons). These isotopes of element 113 are also radioactive and underwent further α-decay processes to isotopes of element 111 and so on down to at least element 105 (dubnium). One of the nuclei took over a second to decay to element 111.

²⁸⁷₁₁₅Uup → ²⁸³₁₁₃Uut + ⁴₂He (46.6 milliseconds) → ²⁷⁹₁₁₁Uuu + ⁴₂He (147 milliseconds)

²⁸⁸₁₁₅Uup → ²⁸⁴₁₁₃Uut + ⁴₂He (80.3 milliseconds) → ²⁸⁰₁₁₁Uuu + ⁴₂He (376 milliseconds)

²⁸⁸₁₁₅Uup → ²⁸⁴₁₁₃Uut + ⁴₂He (18.6 milliseconds) → ²⁷⁹₁₁₁Uuu + ⁴₂He (1196 milliseconds)

²⁸⁸₁₁₅Uup → ²⁸⁴₁₁₃Uut + ⁴₂He (280 milliseconds) → ²⁷⁹₁₁₁Uuu + ⁴₂He (517 milliseconds)