Meitnerius . Element expected to be chemically similar to the element iridium. An atom has been produced and its decay has been observed in the fusion reaction between 58Fe and 209Bi.
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- 1 History
- 2 Obtaining
- 3 Health effects
- 4 Environmental effects
- 5 Sources
The meitnerio was synthesized for the first time the 29 of August of 1982 by a German research team led by Peter Armbruster and Gottfried Münzenberg at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung) in Darmstadt . The team did this by bombarding bismuth -209 with accelerated -58 iron cores . The creation of this element demonstrated that nuclear fusion techniques could be used to create new heavy nuclei. The name Meitnerium was suggested in honor of the Austrian and Swedish mathematician and physicist Lise Meitner, but there was a controversy about the names of the elements between 101 and 109; thus, the IUPAC adopted the name unnilennio (symbol Une) temporarily, as the systematic name of the element. In 1997 , they decided the dispute and adopted the current name.
This experiment was carried out in 1982 by the same German team that discovered the element Bh, using the same techniques. A total dose of 7×1017 ions was used to bombard thin layers of bismuth, during an irradiation time of 250 h. The excitation energy of the composite system fits well to the systematics for a reaction channel of a neutron leading to the 266Mt isotope according to the assignment that follows from its decay properties per alpha particle (11.1 MeV) is within the expected from the systematics of the decay energies per alpha particle. A half-life of between 2 and 20 ms has been estimated.
The cross section for a production is extremely small (approximately 10-39 m2). Out of 1011 nuclear encounters, apparently only one leads to the production of an atom of the Mt element. However, the probability of producing the randomly observed event is 10-18. Even with a single atom found, the existence of the element Mt can be considered highly probable. Yu. Ts. Oranessian and his team at Dubna repeated the Darmstadt experiment in 1984 , with a radiation dose ten times higher.
Nucleide 246Cf, an alpha emitter with a half life of 1.5 days and the seventh member of the decay chain, was chemically separated. It was recorded that there were seven alpha decays that were compatible with the decay energy and half-life of 246Cf. Additionally, a fission event of 258Rf was observed. Thus, the formation of this 266Mt isotope has been indirectly confirmed.
Being so unstable, any amount formed will break down into other elements so quickly that there is no reason to study its effects on human health.
Due to its extremely short half-life (3.8 milliseconds), there is no reason to consider the effects of meitnerium in the environment.