scholarly journals Chemistry of the superheavy elements

2015 ◽  
Vol 373 (2037) ◽  
pp. 20140191 ◽  
Author(s):  
Matthias Schädel
Keyword(s):  
Periodic Table ◽  
Nuclear Reactions ◽  
Noble Gas ◽  
Relativistic Quantum ◽  
Chemical Properties ◽  
Relativistic Effects ◽  
Electron Shell ◽  
Heavy Ion ◽  
Superheavy Elements ◽  
Shell Effects

The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently ‘known’ SHEs (11 are officially ‘discovered’ and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe ‘relativistically’ influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models.

scholarly journals Synthesis and Study of the New Superheavy Elements of D.I. Mendeleev Periodic Table of the Elements

Vestnik RFFI ◽  
2019 ◽  
pp. 87-104
Author(s):  
Yuri Ts. Oganessian
Keyword(s):  
Periodic Table ◽  
Nuclear Reactions ◽  
Chemical Properties ◽  
Nuclear Research ◽  
Superheavy Elements ◽  
Fusion Reactions ◽  
Flerov Laboratory ◽  
The Sixties ◽  
Experimental Complex ◽  
Physical And Chemical

In the sixties of the XX century, the possibility of existence of the region of increased stability of superheavy nuclei in the vicinity of Z | 114 and N | 184 was proved. For the first time a successful synthesis of superheavy elements was carried out in the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research (JINR). Superheavy elements of D.I. Mendeleev Periodic Table of the Elements with atomic numbers 114–118 were synthesized in the fusion reactions of the nuclei of the transuranic elements with calcium-48 nuclei. The article deals with the choice of reactions for the synthesis of new elements, methods of studying their nuclear-physical and chemical properties. The experimental complex “Factory of superheavy elements” created in JINR and prospects of further research development are described.

scholarly journals The periodic table – an experimenter’s guide to transactinide chemistry

2019 ◽  
Vol 107 (9-11) ◽  
pp. 865-877 ◽  
Author(s):  
Robert Eichler
Keyword(s):  
Research And Development ◽  
Gas Phase ◽  
Periodic Table ◽  
Chemical Properties ◽  
Superheavy Elements ◽  
Experimental Results ◽  
Chemical Studies ◽  
Phase Chemical

Abstract The fundamental principles of the periodic table guide the research and development of the challenging experiments with transactinide elements. This guidance is elucidated together with experimental results from gas phase chemical studies of the transactinide elements with the atomic numbers 104–108 and 112–114. Some deduced chemical properties of these superheavy elements are presented here in conjunction with trends established by the periodic table. Finally, prospects are presented for further chemical investigations of transactinides based on trends in the periodic table.

scholarly journals Radiochemical Research with Transactinide Elements in Switzerland

2020 ◽  
Vol 74 (12) ◽  
pp. 924-931
Author(s):  
Patrick Steinegger ◽  
Robert Eichler
Keyword(s):  
Periodic Table ◽  
Chemical Elements ◽  
Relativistic Effects ◽  
Theoretical Work ◽  
Heavy Ion ◽  
Research Topic ◽  
Ion Accelerator ◽  
International Collaborations ◽  
Paul Scherrer ◽  
Heaviest Elements

Here, we present a review on a fundamental radiochemical research topic performed by Swiss scientists in national and international collaborations, utilizing large accelerator facilities at the Paul Scherrer Institute as well as abroad. The chemical investigation of the heaviest elements of the periodic table is a truly multidisciplinary effort, which allows scientists to venture into a variety of fields ranging from nuclear and radiochemistry to experimental and theoretical work in inorganic and physical chemistry all the way to nuclear and atomic physics. The structure and fundamental ordering scheme of all elements in the periodic table, as established more than 150 years ago, is at stake: The ever increasing addition of new elements at the heavy end of the periodic table together with a growing influence of relativistic effects, raises the question of how much periodicity applies in this region of the table. Research on the heaviest chemical elements requires access to large heavy-ion accelerator facilities as well as to rare actinide isotopes as target materials. Thus, this scientific area is inevitably embedded in joint international efforts. Its fundamental character ensures academic relevance and thereby substantially contributes to the future of nuclear sciences in Switzerland.

Heavy, Superheavy . . . Quo Vadis?

2018 ◽  
Author(s):  
Paul J. Karol
Keyword(s):  
Atomic Number ◽  
Periodic Table ◽  
Chemical Element ◽  
Chemical Elements ◽  
Chemical Properties ◽  
Superheavy Element ◽  
Electron Shell ◽  
Heavy Elements ◽  
Quo Vadis ◽  
Definition Of

Uranium was Discovered in 1789 by the German chemist Martin Heinrich Klaproth in pitchblende ore from Joachimsthal, a town now in the Czech Republic. Nearly a century later, the Russian chemist Dmitri Mendeleev placed uranium at the end of his periodic table of the chemical elements. A century ago, Moseley used x-ray spectroscopy to set the atomic number of uranium at 92, making it the heaviest element known at the time. This chapter will deal with the quest to explore that limit and heavy and superheavy elements, and provide an update on where continuation of the periodic table is headed and some of the significant changes in its appearance and interpretation that may be necessary. Our use of the term “heavy elements” differs from that of astrophysicists who refer to elements above helium as heavy elements. The meaning of the term “superheavy” element is still not exactly agreed upon and has changed over the past several decades. “Ultraheavy” is occasionally used. Interestingly, there is no formal definition of “periodic table” by the International Union of Pure and Applied Chemistry (IUPAC) in their glossary of definitions: the “Gold Book.” But there are plenty of definitions in the general literature—including Wikipedia, the collaborative, free, internet encyclopedia which calls the “periodic table” a “tabular arrangement of the chemical elements, organized on the basis of their atomic numbers, electron configurations (electron shell model), and recurring chemical properties. Elements are presented in order of increasing atomic number (the number of protons in the nucleus).” IUPAC’s first definition of a “chemical element” is: “A species of atoms; all atoms with the same number of protons in the atomic nucleus.” Their definition of atom: “the smallest particle still characterizing a chemical element. It consists of a nucleus of positive charge (Z is the proton number and e the elementary charge) carrying almost all its mass (more than 99.9%) and Z electrons determining its size.”

NEW EXPERIMENTAL APPROACH FOR HEAVY AND SUPERHEAVY ELEMENT PRODUCTION

2009 ◽  
Vol 18 (04) ◽  
pp. 1036-1043 ◽  
Author(s):  
M. BARBUI ◽  
T. MATERNA ◽  
P. SAHU ◽  
A. WIELOCH ◽  
F. D. BECCHETTI ◽  
...  
Keyword(s):  
Experimental Approach ◽  
Nuclear Reactions ◽  
Superheavy Element ◽  
Heavy Ion ◽  
Superheavy Elements ◽  
Preliminary Results

In this article we present a new experimental approach for production of heavy and superheavy elements (HE, SHE). Nuclear reactions at low incident energies induced by heavy ion (HI) projectiles on fissile target nuclei are investigated. Dedicated detection setup is presented and the preliminary results for the reaction 197Au(7.5 MeV /u) + 232Th, studied at the Cyclotron Institute of Texas A&M University, are given.

Synthesis and decay properties of superheavy elements

2006 ◽  
Vol 78 (5) ◽  
pp. 889-904 ◽  
Author(s):  
Yuri Oganessian
Keyword(s):  
Nuclear Reactions ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Radioactive Decay ◽  
Parent Nucleus ◽  
Heavy Ion ◽  
Superheavy Elements ◽  
Neutron Excess ◽  
Decay Properties ◽  
Neutron Rich Isotope

A fundamental outcome of modern nuclear theory is the prediction of the "island of stability" in the region of hypothetical superheavy elements. A significant enhancement in nuclear stability at approaching the closed shells with Z = 114 (possibly 120 and 122) and N = 184 is expected for the nuclei with large neutron excess. For this reason, for the synthesis of nuclei with Z = 112-116 and 118, we chose the reactions 238U, 242,244Pu, 243Am, 245,248Cm, and 249Cf + 48Ca, which are characterized by fusion products with a maximal neutron excess. The formation and decay properties of the heaviest nuclei were registered with the use of a gas-filled recoil separator installed at a 48Ca-beam of the heavy-ion cyclotron. The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission (SF). The total time of decay ranges from 0.5 ms to ~1 d, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268Db (TSF ~ 30 h), the final product in the chain of α-decays of the odd-odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104-118 and N = 162-177 gives evidence of the decisive influence of the structure of superheavy elements on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature are also presented.The experiments were carried out at the Flerov Laboratory of Nuclear Reactions (JINR, Dubna) in collaboration with the Analytical and Nuclear Chemistry Division of the Lawrence Livermore National Laboratory (USA).

Relativity in the electronic structure of the heaviest elements and its influence on periodicities in properties

2019 ◽  
Vol 107 (9-11) ◽  
pp. 833-863 ◽  
Author(s):  
Valeria Pershina
Keyword(s):  
Periodic Table ◽  
Chemical Properties ◽  
Relativistic Effects ◽  
Experimental Investigations ◽  
Close Link ◽  
Chemical Studies ◽  
Heaviest Elements ◽  
Chemical Groups ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractTheoretical chemical studies demonstrated crucial importance of relativistic effects in the physics and chemistry of superheavy elements (SHEs). Performed, with many of them, in a close link to the experimental research, those investigations have shown that relativistic effects determine periodicities in physical and chemical properties of the elements in the chemical groups and rows of the Periodic Table beyond the 6thone. They could, however, also lead to some deviations from the established trends, so that the predictive power of the Periodic Table in this area may be lost. Results of those studies are overviewed here, with comparison to the recent experimental investigations.

Viatscheslaw Romanoff: unknown genius of the periodic system

2019 ◽  
Vol 91 (12) ◽  
pp. 1921-1928 ◽  
Author(s):  
Mikhail Kurushkin
Keyword(s):  
Periodic System ◽  
Periodic Table ◽  
Precious Metal ◽  
Chemical Elements ◽  
Noble Gas ◽  
Chemical Properties ◽  
Correct Placement ◽  
History Of ◽  
Actinide Series ◽  
And Chemical Properties

Abstract The history of chemistry has not once seen representations of the periodic system that have not received proper attention or recognition. The present paper is dedicated to a nearly unknown version of the periodic table published on the occasion of the centenary celebration of Mendeleev’s birth (1934) by V. Romanoff. His periodic table visually merges Werner’s and Janet’s periodic tables and it is essentially the spiral periodic system on a plane. In his 1934 paper, Romanoff was the first one to introduce the idea of the actinide series, a decade before Glenn T. Seaborg, the renowned creator of the actinide concept. As a consequence, another most outstanding thing about Romanoff’s paper occurs towards its very end: he essentially predicted the discovery of elements #106, #111 and #118. He theorized that, had uranium not been the “creative limit”, we would have met element #106, a “legal” member of group 6, element #111, a precious metal, “super-gold” and element #118, a noble gas. In 2019, we take it for granted that elements #106, #111 and #118 indeed exist and they are best known as seaborgium, roentgenium and oganesson. It is fair to say that Romanoff’s success with the prediction of correct placement and chemical properties of seaborgium, roentgenium and oganesson was only made possible due to the introduction of an early version of the actinide series that only had four elements at that time. Sadly, while Professor Romanoff was imprisoned (1938–1943), two new elements, neptunium (element #93) and plutonium (element #94) were discovered. While Professor Romanoff was in exile in Ufa (1943–1953), six further elements were added to the periodic table: americium (element #95), curium (element #96), berkelium (element #97), californium (element #98), einsteinium (element #99) and fermium (element #100). The next year after his death, in 1955, mendelevium (element #101), was discovered. Romanoff’s version of the periodic table is an unparalleled precursor to the contemporary periodic table, and is an example of extraordinary anticipation of the discovery of new chemical elements.

Development of nuclear chemistry at Mainz and Darmstadt

2018 ◽  
Vol 107 (1) ◽  
pp. 1-25
Author(s):  
Jens-Volker Kratz
Keyword(s):  
Relativistic Quantum ◽  
Chemical Properties ◽  
Fission Products ◽  
Heavy Ion ◽  
Resonance Ionization ◽  
Ionization Mass ◽  
Nuclear Chemistry ◽  
Laser Technique ◽  
Detection Techniques ◽  
Chemical Separations

Abstract This review describes some key accomplishments of Günter Herrmann such as the establishment of the TRIGA Mark II research reactor at Mainz University, the identification of a large number of very neutron-rich fission products by fast, automated chemical separations, the study of their nuclear structure by spectroscopy with modern detection techniques, and the measurement of fission yields. After getting the nuclear chemistry group, the target laboratory, and the mass separator group established at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, a number of large international collaborations were organized exploring the mechanism of deeply inelastic multi-nucleon transfer reactions in collisions of Xe and U ions with U targets, Ca and U ions with Cm targets, and the search for superheavy elements with chemical separations after these bombardments. After the Chernobyl accident, together with members of the Institute of Physics, a powerful laser technique, the resonance ionization mass spectometry (RIMS) was established for the ultra-trace detection of actinides and long-lived fission products in environmental samples. RIMS was also applied to determine with high precision the first ionization potentials of actinides all the way up to einsteinium. In the late 1980ies, high interest arose in results obtained in fusion-evaporation reactions between light projectiles and heavy actinide targets investigating the chemical properties of transactinide elements (Z≥104). Remarkable was the observation, that their chemical properties deviated from those of their lighter homologs in the Periodic Table because their valence electrons are increasingly influenced by relativistic effects. These chemical results could be reproduced with relativistic quantum-chemical calculations. The present review is selecting and describing examples for fast chemical separations that were successful at the TRIGA Mainz and heavy-ion reaction studies at GSI Darmstadt.

scholarly journals Superheavy elements

2019 ◽  
Vol 89 (6) ◽  
pp. 563-570
Author(s):  
Yu. Ts. Oganessian
Keyword(s):  
Periodic Table ◽  
Nuclear Reactions ◽  
Nuclear Research ◽  
Superheavy Elements ◽  
Superheavy Nuclei ◽  
Fusion Reactions ◽  
Nuclear Theory ◽  
Oak Ridge ◽  
Flerov Laboratory ◽  
Heaviest Elements

Synthesis of superheavy elements predicted by microscopic nuclear theory is investigated. The heaviest elements with Z = 114–118 were synthesized by fusion reactions of actinide nuclei with 48Ca ions accelerated using the U-400 complex at the Flerov Laboratory of Nuclear Reactions (FLNR), one of seven laboratories that comprise the Joint Institute for Nuclear Research (JINR) located in Dubna, Russia. The experiments were carried out in collaboration with physicists and chemists working at the Livermore and Oak Ridge national laboratories in located in California and Tennessee, respectively. Discovery of these elements allowed completion of the seventh period of the periodic table. The microscopic nuclear theory’s fundamental predictions about the possible existence of superheavy elements received the experimental confirmation. A new laboratory, i.e., the "STE Factory" associated with the JINR FLNR, has been established to research superheavy nuclei.

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