Meitnerium is a synthetic element that was discovered in 1982. It is a highly radioactive and unstable element.
History and Discovery
According to the Mendeleev’s nomenclature of undiscovered elements, meitnerium was named element-109. In 1982, Peter Armbruster and Gottfried Münzenberg led a research team at the Institute for Heavy Ion Research (GSI), Germany, bombarded a bismuth-209 target with nuclei of iron-58 and produced one atom the 109th element, meitnerium-266 [1]. The element was named in honour of Australian physicist Lise Meitner, who was one of the discoverers of nuclear fission [2]. The International Union of Pure and Applied Chemistry approved the name meitnerium in 1994. Its symbol is Mt.
Meitnerium
| Periodic Table Classification | Group 9 Period 7 |
|---|---|
| State at 20C | Solid (predicted) |
| Color | Unknown |
| Electron Configuration | [Rn] 5f14 6d7 7s2 (calculated) |
| Electron Number | 109 |
| Proton Number | 109 |
| Electron Shell | 2, 8, 18, 32, 32, 15, 2 (predicted) |
| Density | 37.40 g.cm-3 at 20°C (predicted) |
| Atomic number | 109 |
| Atomic Mass | 268.00 g.mol -1 |
| Electronegativity according to Pauling | n/a |
Occurrence
Meitnerium is an artificial element and does not exist in nature.
Physical Characteristics
Meitnerium is predicted to be a solid under normal conditions. It is expected to be have a very high density of around 37.7 g/cm3, which make it the second heaviest of all known 118 known elements. The amount of meitnerium produced so far and its extremely short half-life has made it difficult to carry out analysis of its physical and chemical characteristics [3].
Chemical Characteristics
Meitnerium is predicted to be a nobel element, however, the chemical characteristics of meitnerium are not well studied yet. It is predicted to chemically resemble iridium, cobalt and rhodium (Group IX elements). It is expected to readily react with oxygen and form a tetroxide that is highly volatile. Meitnerium has been placed as the 7th member of the 6d series of transition metals. It is member of the group 9th and 7th period of the periodic table. The most stable oxidation state of meitnerium has been proposed to be +6, +1 and +3.
Significance and Uses
- Meitnerium is used for research purposes.
Health Hazards
Meitnerium is a highly radioactive element and requires special precautions with handling and storage.
Isotopes of Meitnerium
There are eight different isotopes of meitnerium, that range in atomic masses: 266, 268, 270, 274, 275, 276, 277 and 278. They are unstable and unnatural. The heavier isotopes are more stable as compared to lighter isotopes. And the most stable isotope is meitnerium-278, having a half-life of 7.6 seconds. Most of the radioisotopes decay through emission of alpha particles while some undergo spontaneous fission [4].
REFERENCES
[1]. Barber, R. C.; Greenwood, N. N.; Hrynkiewicz, A. Z.; Jeannin, Y. P.; Lefort, M.; Sakai, M.; Ulehla, I.; Wapstra, A. P.; Wilkinson, D. H. (1993). “Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements”. Pure and Applied Chemistry. 65 (8): 1757. doi:10.1351/pac199365081757. (Note: for Part I see Pure Appl. Chem., Vol. 63, No. 6, pp. 879–886, 1991)
[2]. Wiesner, Emilie; Settle, Frank A. (2001). “Politics, Chemistry, and the Discovery of Nuclear Fission”. Journal of Chemical Education. 78 (7): 889. Bibcode:2001JChEd..78..889W. doi:10.1021/ed078p889.
[3]. Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). “Transactinides and the future elements”. In Morss; Edelstein, Norman M.; Fuger, Jean. The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 1-4020-3555-1.
[4]. Sonzogni, Alejandro. “Interactive Chart of Nuclides”. National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06