Hassium element isotopes

Most of the chemical and physical properties of imniloctium (hassium) are unknown. What is known is that its most stable isotope (hassium-108) has the atomic weight (mass) of about 277. Hs-277 has a half-life of about 12 minutes, after which it decays into the isotope seaborgium-273 through either alpha decay or spontaneous fission. Hassium is the last element located at the bottom of group 8, and like element 107, it is produced by a cold fusion process that in hassium s case is accomplished by slamming iron (Fe-58) into particles of the isotope of lead (Pb-209), along with several neutrons, as follows ... 

In December 1998 the Lawrence Berkeley Laboratory sent a supply of plutonium-244 and calcium-48 to Russian scientists at the Joint Institute of Nuclear Research in Dubna, Russia. The Russians bombarded the plutonium with ions of calcium, which, after some time, produced a single atom of ununquadium-289. Uuq has a half-life of just 30 seconds, after which it decays successively into element 112 (ununbium), element 110, (darmstadtium), and element 108 (hassium). The Russian nuclear laboratory later synthesized several atoms of other isotopes of Ununquadium. 

CAS 54037-57-9[. Hassium is a chemical clement in the periodic table that has the symbol Hs and atomic number 108. It is a synthetic element whose most stable isotope is Hs-265. with a half-life of 2 ms. It was first synthesized in 1984 by a German research team led by Peter Armbruster and Gottfried MUnzenbcrg at Ihe Institute for Heavy Ion Research at Darmstadt The name hassium was proposed by them, derived from the... 

Yakushev, A.B., Vakatov, V.I., Vasko, V., Lebedev, V.Ya., Timokhin, S.N., Tsyganov, Yu.S., Zvara, I. "On-line Experiments with Short-lived Osmium Isotopes as a Test of the Chemical Identification of the Element 108 - Hassium" In Extended Abstracts of "1st International Conference on Chemistry and Physics of the Transactinide Elements", Seeheim, Germany, 26-30 September 1999, P-M-17. 

Hassium — (named for the German state, Hesse) Hs at. wt. [277] at. no. 108. This element was first synthesized and identified in 1964 by the same G.S.I. Darmstadt Group who first identified Bohrium and Meitnerium. Presumably this element has chemical properties similar to osmium. Isotope 108 was produced using a beam of Fe projectiles, produced by the Universal Linear Accelerator (UNILAC) to bombard a Pb target. Discovery oiBohrium Bind Meitnerium was made using detection of isotopes with odd proton and neutron numbers. 

Element 108 was synthesized by the Darmstadt team in 1984 by bombarding ° Pb with Fe ions to create an element of mass 265. The element was later named hassium (Hs) after the state of Hessen, which includes the city of Darmstadt. The most stable isotope of hassium is °Hs, ty, 21 seconds. Extremely skilled online chemical investigations of this short-lived, ultrarare substance demonstrated the formation and some properties of HSO4, bearing similarity to its Group 8 relative OSO4. 

Hassium (Hs), Z = 108 was discovered in the reaction Pb( Fe, n) Hs (Miinzenberg et al. 1984b, 1987) and unambiguously confirmed in a later experiment (Hofmann et al. 1995a). This element was synthesized after meitnerium as theoretical predictions available at that time suggested the predominance of spontaneous fission with half-lives below microseconds for the doubly even hassium isotopes (Randrup et al. 1976). Hence, to proceed with the synthesis of meitnerium was considered to be safer since it was possible to profit twice fi-om the fission hindrance provided by the odd proton and the odd neutron, if an odd-odd nuclide was to be produced. The resulting observation of a decay is necessary for the identification of the new element with the correlation method. The synthesis of hassium with the unexpected... 

In 1984 P. Armbruster s group at the Institute for Heavy Ion Research at Darmstadt bombarded lead-208 atoms with ions of iron-58. In 10 days of bombardment, they successfully produced three atoms of an isotope of element 108 with mass number 265. They suggested that the new element should be named hassium, which is derived from the Latin name Hassias for the German state of Hessen, in which the institute is situated. The name hassium Hs was adopted internationally in 1997. 

Hassium (Z = 108) is the lightest superheavy element that has been produced directly in " Ca-induced reactions. The 20-s isotope °Hs has been produced in the Ra(" Ca,4n) reaction with a cross section of 8 pb [133]. Difficulties in target handling and a limited cross section favor the production of this isotope via the hot-fusion reaction " Cm( Mg,4n) for radiochemistry experiments [179, 180] (see Sect. 2.2 and Gas-Phase Chemistry of Superheavy Elements ). A single... 

Under this constraint, it is not possible to produce new superheavy nuclides at greater neutron excess by cold fusion, or by hot fusion with heavy-ion beams with lower atomic numbers than argon. This is because of the neutron richness of the overshoot isotopes, daughters of the multiple emission of relatively proton-rich a particles in the decays of the " Ca-induced evaporation residues. Nevertheless, both reaction types offer advantages in the production rates of the known isotopes of superheavy elements with Z = 106-108 that are of interest to the radiochemist. As examples Direct production of the long-lived hassium isotope Hs is possible in the cold-fusion irradiation of ° Pb with radioactive Fe. From Fig. 2, the cross... 

It was emphasized in [1] that the nuclear decay properties of the isotope to be used in these studies must be well known and have unique decay characteristics suitable for detection and positive identification on an atom-at-a-time basis in order to verify that it is from the element whose chemistry is to be studied It must have a half-life comparable to the proposed chemical separation procedure as well as a reasonable production and detection rate to permit statistically significant results to be obtained, and must give the same results for a few atoms as for macro amounts. For the transactinide elements, production rates range from a few atoms per minute for rutherfordium (Rf, Z = 104) to only about one atom per day in the case of elements 108 (hassium, Hs), 112, and 114, the heaviest elements studied to date with chemical techniques. Details of these chemical investigations are outlined in Liquid-Phase Chemistry of Superheavy Elements and Gas-Phase Chemistry of SuperheavyElements . 

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