nihonium


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nihonium

(nĭhō`nēəm), artificially produced radioactive chemical element; symbol Nh; at. no. 113; mass number of most stable isotope 284; m.p., b.p., sp. gr., and valence unknown. Situated in Group 13 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
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, it is expected to have properties similar to those of thalliumthallium
, metallic chemical element; symbol Tl; at. no. 81; interval in which at. wt. ranges 204.382–204.385; m.p. 303.5°C;; b.p. about 1,457°C;; sp. gr. 11.85 at 20°C;; valence +1 or +3.
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 and indiumindium
, a metallic chemical element; symbol In; at. no. 49; at. wt. 114.818; m.p. 156.6°C;; b.p. about 2,080°C;; sp. gr. 7.31 at 20°C;; valence +1, +2, or +3. Indium is a soft, malleable, ductile, lustrous, silver-white metallic element; it crystallizes in a
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.

In an experiment in 2003, scientists from the Joint Institute for Nuclear Research in Dubna, Russia, and Lawrence Livermore National Laboratory in California collaborated in the reported discovery of element 113. They bombarded atoms of americiumamericium
, artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175°C;; b.p. about 2,600°C;; sp. gr. 13.67 at 20°C;; valence +2, +3, +4, +5, or +6.
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-243 with ions of calciumcalcium
[Lat.,=lime], metallic chemical element; symbol Ca; at. no. 20; at. wt. 40.078; m.p. about 839°C;; b.p. 1,484°C;; sp. gr. 1.55 at 20°C;; valence +2. Calcium is a malleable, ductile, silver-white, relatively soft metal with face-centered, cubic crystalline
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-48. Among the products of the bombardment were four atoms of moscoviummoscovium
, artificially produced radioactive chemical element; symbol Mc; at. no. 115; mass number of most stable isotope 288; m.p., b.p., sp. gr., and valence unknown.
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 (element 115), which in less than one tenth of a second decayed into atoms of element 113 by emitting an alpha particle. Two isotopes of element 113 were identified, the longer-lived (Nh-284) having a half-life of about 48 msec, and the other (Nh-283) a half-life of about 46.6 msec. The same team later reported creating nihonium-285 by bombarding neptuniumneptunium
, radioactive chemical element; symbol Np; at. no. 93; mass number of most stable isotope 237; m.p. about 640°C;; b.p. 3,902°C; (estimated); sp. gr. 20.25 at 20°C;; valence +3, +4, +5, or +6. Neptunium is a ductile, silvery radioactive metal.
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-237 with calcium-48 in 2007. Researchers at Japan's RIKEN Linear Accelerator Facility in Wako also have reported creating the element, with their first results in 2004. They used a bismuthbismuth
[Ger. Weisse Masse=white mass], metallic chemical element; symbol Bi; at. no. 83; at. wt. 208.98040; m.p. 271.3°C;; b.p. about 1,560°C;; sp. gr. 9.75 at 20°C;; valence +3 or +5.
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-209 target, which was bombarded with zinczinc,
metallic chemical element; symbol Zn; at. no. 30; at. wt. 65.38; m.p. 419.58°C;; b.p. 907°C;; sp. gr. 7.133 at 25°C;; valence +2. Zinc is a lustrous bluish-white metal. It is found in Group 12 of the periodic table.
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-70 to produce nihonium-279 (2004) and nihonium-278 (2012). In 2015, after review, the International Union of Pure and Applied Chemistry (IUPAC) awarded credit for the discovery of element 113 to the RIKEN group. The name nihonium, to honor Japan, was suggested by the element's discoverers in 2016 and approved by IUPAC later that year.

See also synthetic elementssynthetic elements,
in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no.
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; transactinide elementstransactinide elements
, in chemistry, elements with atomic numbers greater than that of lawrencium (at. no. 103), the last member of the actinide series. See transuranium elements.
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; transuranium elementstransuranium elements,
in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ.
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.