Roentgenium is an artificial and highly radioactive element that was synthesized in 1994. It is used for various research purposes.
History and Discovery
Roentgenium is a synthetic element. It was predicted by Mendeleev and was named eka-gold and later was named as the element 111. Roentgenium was synthesized for the first time by a team of researchers led by Sigurd Hofmann in December 1994, who worked at GSI Helmholtz Centre for Heavy Ion Research, Germany. The bismuth-209 isotope was bombarded by nickel-62 which produced a single atom of isotope roentgenium-272 [1]. Using the same approach, three more atoms of roentgenium-272 were produced in 2002. The name roentgenium has been given in honor of the contributions of physicist Wilhelm Rontgen who discovered the X-rays.
Roentgenium
| Periodic Table Classification | Group 11 Period 7 |
|---|---|
| State at 20C | Solid (predicted) |
| Color | Silvery (predicted) |
| Electron Configuration | [Rn] 5f14 6d9 7s2 (predicted) |
| Electron Number | 111 |
| Proton Number | 111 |
| Electron Shell | 2, 8, 18, 32, 32, 17, 2 (predicted) |
| Density | 28.70 g.cm-3 at 20°C (predicted) |
| Atomic number | 111 |
| Atomic Mass | 282.00 g.mol -1 (most stable isotope) |
| Electronegativity according to Pauling | n/a |
Occurrence
Roentgenium does not occur in nature. It is a synthetic element and is highly unstable. It has a half-life of few seconds.
Physical Characteristics
Roentgenium exists in solid form under normal conditions. It crystallizes in a cubic structure that has a body-centered symmetry. Roentgenium is thought to be a very dense metal and would have a density of round 28.7 g/cm3. But due to its unstable nature, the physical properties can only be predicted or theoretically calculated. Further, creating that much sample of roentgenium to study its physical and chemical properties is difficult as it would undergo spontaneous decay within minutes.
Chemical Characteristics
Roentgenium is extremely radioactive element. The chemical characteristics of roentgenium have not been studied in detail yet [2]. it has been predicted to be a Nobel element. And based in the oxidation’s states of other member of its group (Group 11), the common oxidation states of roentgenium include +5 and +3. It has similar reactivity as gold but is thought to produce more stable and diverse compounds. Roentgenium has also been predicted to form compounds with hydrogen, ammonia and phosphine. The extremely short half-lives of isotopes and highly volatile nature of its compounds make the statistically significant chemical analysis a challenge. Further, the rate of production of roentgenium isotopes need to be at least one per week in order to obtain considerable amount of the element.
Significance and Uses
- Roentgenium and its various isotopes are used for research and laboratory purposes.
Health Effects
Roentgenium is highly radioactive and require special handling precautions.
Isotopes of Roentgenium
There are nine isotopes of roentgenium. There are no stable or natural isotopes of roentgenium. The isotopes are produced by decay of heavier element or by the fusion of nuclei of light elements. The isotopes have atomic masses: 272, 274, 278, 279, 280, 281, 282, 283, and 286. [3]. The heavier isotopes are more stable as compared to lighter ones. And the heaviest isotope, roentgenium-282 has a half-life of 2.1 minutes. All the isotopes undergo decay through alpha decay or spontaneous fission, and none of the isotopes undergoes beta decay.
REFERENCES
[1]. Hofmann, S.; Ninov, V.; Heßberger, F. P.; Armbruster, P.; Folger, H.; Münzenberg, G.; Schött, H. J.; Popeko, A. G.; Yeremin, A. V.; Andreyev, A. N.; Saro, S.; Janik, R.; Leino, M. (1995). “Production and decay of 269110″. Zeitschrift für Physik A. 350 (4): 277. Bibcode:1995ZPhyA.350..277H. doi:10.1007/BF01291181
[2]. Düllmann, Christoph E. (2012). “Superheavy elements at GSI: a broad research program with element 114 in the focus of physics and chemistry”. Radiochimica Acta. 100 (2): 67–74. doi:10.1524/ract.2011.1842.
[3]. Sonzogni, Alejandro. “Interactive Chart of Nuclides”. National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06.