| Discovery date | 1994 |
| Discovered by | Peter Armbruster and Gottfried Münzenberg |
| Origin of the name | The name roentgenium (Rg) was proposed by the GSI team in honour of the German physicist Wilhelm Conrad Röntgen, and was accepted as a permanent name on November 1, 2004 |
| Allotropes |
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Rg
Roentgenium
111
[280]
| Group | 11 | Melting point | Unknown |
| Period | 7 | Boiling point | Unknown |
| Block | d | Density (g cm−3) | Unknown |
| Atomic number | 111 | Relative atomic mass | [280] |
| State at 20°C | Solid | Key isotopes | 280Rg |
| Electron configuration | [Rn] 5f146d107s1 | CAS number | 54386-24-2 |
| ChemSpider ID | - | ChemSpider is a free chemical structure database | |
Image explanation
Roentgenium is named after Wilhelm Conrad Röntgen, the discoverer of x-rays. The image is based on an early x-ray tube. The background design is inspired by x-ray astronomy and particle accelerators.
Appearance
A highly radioactive metal, of which only a few atoms have ever been made.
Uses
At present, it is only used in research.
Biological role
Roentgenium has no known biological role.
Natural abundance
A man-made element of which only a few atoms have ever been created. It is made by fusing nickel and bismuth atoms in a heavy ion accelerator.
There are seven known isotopes of the element: 272, 274 and 278-282. The longest lived is isotope 281 which has a half-life of 22.8 seconds. In 1986, physicists at the Russian Joint Institute for Nuclear Research (JINR), bombarded bismuth with nickel hoping to make element 111, but they failed to detect any atoms of element 111. In 1994, a team led by Peter Armbruster and Gottfred Munzenberg at the German Geselleschaft für Schwerionenforschung (GSI), were successful when they bombarded bismuth with nickel and they obtained few atoms of isotope 272. It had a half-life of 1.5 milliseconds.
| Atomic radius, non-bonded (Å) | Unknown | Covalent radius (Å) | 1.21 |
| Electron affinity (kJ mol−1) | Unknown |
Electronegativity (Pauling scale) |
Unknown |
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Ionisation energies (kJ mol−1) |
1st
-
2nd
-
3rd
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4th
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5th
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6th
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7th
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8th
-
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| Common oxidation states | Unknown | ||||
| Isotopes | Isotope | Atomic mass | Natural abundance (%) | Half life | Mode of decay |
| 280Rg | 280.165 | - | ~ 3.6 s | α | |
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Specific heat capacity (J kg−1 K−1) |
Unknown | Young's modulus (GPa) | Unknown | |||||||||||
| Shear modulus (GPa) | Unknown | Bulk modulus (GPa) | Unknown | |||||||||||
| Vapour pressure | ||||||||||||||
| Temperature (K) |
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| Pressure (Pa) |
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| Listen to Roentgenium Podcast |
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Transcript :
Chemistry in its element: roentgenium(Promo) You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry. (End promo) Meera Senthilingam This week an element that needs just the right conditions in order to get a successful collision. Here's Simon Cotton: Simon Cotton I used to be able to go into my chemistry lab, look the pupils in the eye, and say 'U-U-U'. And they would say 'What have I done, Sir?' 'You've done nothing wrong' I would reply, 'I am talking about Element 111, unununium, symbol Uuu'. So I was a bit sad when in 2004 a joint working party of the International Union of Pure and Applied Chemistry and International Union of Pure and Applied Physics recommended that the name of element 111 be changed to roentgenium, symbol Rg. Roentgenium was in fact discovered 10 years earlier on December 8, 1994, by a team of 13 nuclear physicists working at the Gesellschaft für Schwerionenforschung at Darmstadt in Germany carried out an experiment, bombarding a target of 209Bi with 64Ni ions. The idea was to make the nickel ions penetrate the bismuth nucleus, so that the two nuclei would fuse together, making a bigger atom. The energy of the collision had to be carefully controlled, because if the nickel ions were not going fast enough, they could not overcome the repulsion between the two positive nuclei, would just fly off the bismuth on contact. However, if the nickel ions had too much energy, the resulting 'compound nucleus' would have so much excess energy that it could undergo fission and just fall apart. The trick was, like Goldilocks' porridge, to be 'just right', so that the fusion of the nuclei would occur, just. Successful collisions would not occur very often, as most of an atom is empty space. The scientists were however able to observe three successful collisions, forming atoms of atomic number 111 and mass 272. They were very short-lived, with a half-life of around 1 ½ milliseconds. The new atoms were identified by following what happened to them when they decayed - they underwent alpha decay successively forming atoms of elements 109, 107, 105 and 103. In further experiments carried out in 2000, the team carried out more bombardments and observed another three more atoms of element 111. This time they followed the decay chains even further, right down to mendelevium-252, element 101. The discovery of this new element was first announced in a paper published early in 1995. It was given a temporary name of unununium, derived from its atomic number, and the symbol Uuu. No permanent name was assigned to element 111, as independent confimation of its existence was needed, and this did not happen until 2003, when a team at the RIKEN Linear Accelerator facility in Japan made 14 atoms of this isotope. The workers at Darmstadt were then given the honor of proposing proposed the name roentgenium, in recognition of Wilhelm Conrad Roentgen, who discovered X-rays in 1895. No one knows for sure what roentgenium looks like, but it has been placed under copper, silver and gold in the Periodic Table. Theoretical chemists have had fun predicting its properties, and they think that if anyone ever sees any roentgenium metal, it is likely to be silver in colour and it will be very unreactive. Its chemistry is predicted to involve the +3 and +5 oxidation states. When scientists made element 115 back in 2004, they identified in its decay chain a roentgenium isotope of mass 280 with a half life of about 3.6 seconds. So if it can be made directly, there is the possibility of real chemical reactions being studied. So, ladies and gentlemen, that is roentgenium, which looks like being a very precious metal, albeit only for a few seconds. Meera Senthilingam So blink and you may just miss the magic. That was Uppingham School's Simon Cotton with the speedy yet precise chemistry of roentgenium. Now next week we've got a two-faced element. Tim Harrison Chlorine is what you might describe as a Jekyll and Hyde element; it is the friend of the synthetic chemist and has found a use in a number of 'nice' applications such as the disinfecting of drinking water and keeping our swimming pools clean. It also has an unpleasant side, being the first chemical warfare agent and taking some of the blame for the depletion of the Earth's ozone layer. Meera Senthilingam So is it friend or is it foe? Join Bristol University's Tim Harrison to find out in next week's Chemistry in its element. Until then I'm Meera Senthilingam and thank you for listening. (Promo) Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements. (End promo)
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Visual Elements images and videos
© Murray Robertson 1998-2017.
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Derived in part from material provided by the British Geological Survey © NERC.
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Produced by The Naked Scientists.
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
© Murray Robertson 1998-2017.
Data
W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
Uses and properties
John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.
Supply risk data
Derived in part from material provided by the British Geological Survey © NERC.
History text
Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Podcasts
Produced by The Naked Scientists.
Periodic Table of Videos
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
