Physical properties
Not many chemical and physical properties of Une (or Mt) are known, but it is artificiallyproduced by the basic process of combining the isotopes of two elements to produce a fewatoms of a heavier isotope in linear accelerators. In this case, the creation of a few atoms ofelement 109 involves a similar nuclear process of fusion as was used for element 108. Thereaction follows:
83Bi-209 +
26Fe-58 →
109Une-266 +
0n-1 (free neutron).
The most stable isotope of unnilennium is meitnerium-276, which has a half-life of about0.72 seconds. Une-276 decays into element 107 (Uns-272 or bohrium-272).
The melting point, boiling point, and density of unnilennium (meitneriumare unknown,as are many of its other chemical and physical properties.
Isotopes
There are five isotopes of unnilennium (meitnerium), ranging from Une-266 toUne-276, and with half-lives ranging from 1.7 milliseconds to 0.72 seconds.
Origin of Name
Named for the Austrian scientist Lise Meitner.
History
On August 29, 1992, Element 109 was made and identified by physicists at the Heavy Ion Research Laboratory (G.S.I.), Darmstadt, Germany, by bombarding a target of
209Bi with accelerated nuclei of
58Fe. The production of Element 109 has been extremely small. It took a week of target bombardment (1011 nuclear encounters) to produce a single atom of 109. Oganessian and his team at Dubna in 1994 repeated the Darmstadt experiment using a tenfold irradiation dose. One fission event from seven alpha decays of 109 was observed, thus indirectly confirming the existence of isotope
266109. In August 1997, the IUPAC adopted the name meitnerium for this element, honoring L. Meitner. Four isotopes of meitnerium are now recognized.
Uses
None, except for research purposes.
Definition
A radioactive metallic element not found naturally on Earth. Only a few atoms of the element have ever been detected; it can be made by bombarding a bismuth target with iron nuclei. The isotope
266Mt has a half-life of about 3.4 × 10
–3s. Symbol: Mt; p.n. 109.
Definition
meitnerium: Symbol Mt. A radioactivetransactinide element; a.n.109. It was first made in 1982 by Peter Armbruster and a team in Darmstadt, Germany, by bombarding bismuth-209 nuclei with iron-58 nuclei.Only a few atoms have ever been detected.
Hazard
None, except for radiation, which is not much of a risk given that only a few atoms existin nuclear laboratories.
