Hassium (Hs)
Hassium (Hs) is a synthetic radioactive metal with the atomic number 108 and a relative atomic mass of 269. It is situated in period 7 of the d-block of the periodic table, between the elements bohrium and meitnerium. Discovered in 1984 by a team led by Peter Armbruster and Gottfried Münzenberg, hassium was created by bombarding lead-208 with iron-58 atoms, resulting in isotopes with extremely short half-lives, the longest being 1.1 hours for hassium-276. The element is named after the German State of Hesse, where it was first produced. Although it is predicted to be a solid, its physical properties remain largely unknown due to its synthetic nature and brief existence. Chemically, hassium shares similarities with osmium and ruthenium, particularly in its volatility and oxidation behavior. However, because it has only been produced in minute quantities and has no recognized practical applications, hassium's research has been limited to laboratory studies.
Subject Terms
Hassium (Hs)
- Element Symbol: Hs
- Atomic Number: 108
- Atomic Mass: 277
- Group # in Periodic Table: 8
- Group Name: Transition metals
- Period in Periodic Table: 7
- Block of Periodic Table: d-block
- Discovered by: Peter Armbruster, Gottfried Münzenberg (1984)
Hassium is a radioactive metal with an atomic number of 108 and relative atomic mass of 269. In the periodic table, it is located between bohrium and meitnerium in period 7 of the d-block. Its chemical symbol is Hs, and its electronic configuration is [Rn] 5f146d67s2. Another name for hassium or element 108 is unniloctium. Hassium is a synthetic element created by Peter Armbruster, Gottfried Münzenberg, and their team in 1984. They bombarded lead-208 with iron-58 atoms in a machine called the linear accelerator that made three atoms of hassium-265 and a free neutron. The atoms had a half-life of only 2 milliseconds. A linear accelerator is a machine that produces high-energy X-rays. These days, it is commonly used in the treatment of cancer patients because the X-rays can destroy cancerous cells.
Hassium was discovered in 1982, two years after the discovery of the element meitnerium; both elements were found by the same scientific team, which included Peter Armbruster and Münzenberg. Hassium got its name from the German State of Hesse, which was where the element was first found.
The first attempt to make hassium was done at Russia’s Joint Institute for Nuclear Research (JINR) in 1978. The project was headed by the scientists Yuri Oganessian and Vladimir Utyonkov. The two scientists bombarded the element radium with calcium and created the isotope 270. In 1983, they acquired other isotopes as well by bombarding the element bismuth with manganese to make isotope 263, by bombarding the element californium with neon to make isotope 270, and by bombarding the element lead with iron to make isotope 264. However, the data that were collected by Armbruster and Münzenberg during their experiments were found to be more reliable than the data collected by the JINR. Their more reliable data gave Armbruster and Münzeberg the naming rights for this element, and they chose the name hassium.
Physical Properties
Because hassium does not occur naturally, it does not have any naturally occurring isotopes. Its melting point, boiling point, and density are all unknown at this time. This is partly due to the element’s extremely short half-life and because only a few atoms have ever been produced. As a result, there have been few studies of its properties. Hassium is predicted to be a solid. Due to its extremely short half-life, its standard state—that is, its state at 298 K—is difficult to accurately determine. It is a toxic heavy metal because of its radioactive properties.
Chemical Properties
Hassium is a synthetic element made only in laboratories, and it is highly radioactive. So far, the fifteen isotopes that have been produced have mass numbers 263 through 277. Hassium-276 is found to have the longest half-life—it is 1.1 hours—and it has chemical properties very similar to the elements osmium (Os) and ruthenium (Ru) based on its location in the periodic table. These elements are highly volatile tetroxides. Hassium is one of the transactinides, and its most unstable isotope is hassium-277, which has a half-life of about 12 minutes. A transactinide element is an element whose atomic number is greater than 103. Most of these elements, which are all artificially produced, include such examples as meitnerium and actinium, among others. According to the National Institutes of Health (NIH), it is difficult to determine which elements can be classified as transactinides—that is, the heaviest elements—because of the strong relativistic effects on the valence electron shells. These effects cause deviations in the elements’ chemical properties from the known chemical trends in the periodic table. The hassium isotope 269, produced by the fusion of magnesium-26 and curium-248, is immediately oxidized to a volatile oxide, presumably HsO4. The enthalpy of adsorption, which can be detected on the surface of a specialized instrument, is assumed to be similar to that of osmium oxide OsO4.This measurement demonstrated that the chemical properties of hassium are similar to those of osmium.
Hassium-265, which was produced by bombarding lead-208 with iron-58, decays to seaborgium-266 through alpha decay. Alpha decay is a type of radioactive decay in which the nucleus of the unstable atom loses two protons and two neutrons to become stable. These two protons and two neutrons together are called an alpha particle. During the process of alpha decay, a larger unstable nucleus turns into a smaller more stable nucleus.
Applications
Most transactinide elements are made in laboratories, but not all research centers have suitable equipment to make such heavy elements. As a result, more than one institution in the past has claimed to be the first to have discovered an element and hence, claimed the right to name it. Often, therefore, these elements end up having more than one name.
Only a few atoms of hassium have ever been produced, and most of the element’s isotopes have half-lives of only fractions of seconds. This is one reason why hassium has not been extensively researched. Given the mysteries surrounding hassium, we know of no biologic or chemical uses for the element. It is only used in research.
Bibliography
"Alpha Decay." Glossary. Jefferson Lab, n.d. Web. 29 Jan. 2016.
Dullmann, C., W. Bruchle, D. Piguet, et al. "Chemical Investigation of Hassium (Element 108)." Nature 418 (22 Aug. 2002): 59–62. Web. 29 Jan. 2016.
"The Element Hassium." It’s Elemental. Jefferson Lab, n.d. 29 Jan. 2016.
Greenwood, Norman N, and Alan Earnshaw. Chemistry of the Elements. 2nd ed. Portsmouth: Butterworth-Heinemann, 1997. Print.
"Hassium." Funk &Wagnalls New World Encyclopedia. World Almanac Education Group, Inc., 2015. Web. 29 Jan. 2016.
"Hassium." Periodic Table.Royal Society of Chemistry, n.d. Web. 29 Jan. 2016.
"Hassium (Hs)." Encyclopaedia Britannica. Encyclopaedia Britannica, Inc., n.d. 30 Jan. 2016.
"Transactinide." The Free Dictionary. Farlex, Inc., n.d. Web. 30 Jan. 2016.