Search results for: the-transactinides

The Transactinides

Author : Linley Erin Hall
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This book explains how three major research groups have worked on creating the transactinide elements in their laboratories and discusses that the transactinides are sometimes called the superheavy elements.

The Transactinides

Author : Linley Erin Hall
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Introduces the Transactinides and teaches how these elements are connected, found, used, and structured.

Nuclear and Radiochemistry

Author : Karl Heinrich Lieser
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Radioactivity in nature Radioelements, Isotopes and radionuclides Physical properties of atomic nuclei and elementary particles Radioactive Decay Decay Modes Nuclear radiation Measurement of nuclear radiation Nuclear reactions Chemical effects of nuclear reactions Influence of chemical bonding on nuclear properties Nuclear energy, nuclear reactors, nuclear fuel and fuel cycles Production of radionuclides and labelled compounds Special aspects of the chemistry of radionuclides Radioelements Radionuclides in Geo- and Cosmochemistry Dating bij nuclear methods Radioanalysis Radiotraces in chemistry Radionuclides in the life sciences Technical and industrial applications of radionuclides and nuclear radiation Radionuclides in the geosphere and the biosphere Dosimetry and radiation protection

Proceedings of the Robert A Welch Foundation Conferences on Chemical Research

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Annual Report

Author : Robert A. Welch Foundation
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Acta Physica Polonica

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Encyclopedia of Chemical Technology A to alkaloids

Author : Raymond Eller Kirk
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Adsorption of the Lighter Homologs of Element 104 and Element 105 on DGA Resin from Various Mineral Acids

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The goal of studying transactinide elements is to further understand the fundamental principles that govern the periodic table. The current periodic table arrangement allows for the prediction of the chemical behavior of elements. The correct position of a transactinide element can be assessed by investigating its chemical behavior and comparing it to that of the homologs and pseudo-homologs of a transactinide element. Homologs of a transactinide element are the elements in the same group of the periodic table as the transactinide. A pseudo-homolog of a transactinide element is an element with a similar main oxidation state and similar ionic radius to the transactinide element. For example, the homologs of rutherfordium, Rf, are titanium, zirconium and hafnium (Ti, Zr and Hf); the pseudo homologs of Rf are thorium, Th, and plutonium, Pu. Understanding the chemical behavior of a transactinide element compared to its homologs and pseudo-homologs also allows for the assessment of the role of relativistic effects. Relativistic effects occur when the velocity of the s orbital electrons closest to the nucleus approaches the speed of light. These electrons approach the speed of light because they have no orbital momentum. This causes two effects, first there is in a decrease in Bohr radius of the inner electronic orbitals because of this there is an increase in particle mass. A contraction of outer s and p orbitals is also seen. The contraction of these orbitals results in an energy destabilization of the outer most shell, in the case of transactinides this would be the 5f and 6d orbitals. The outer most d shell and all f shells can also experience a radial expansion due to these orbitals being screened from the effective nuclear charge. Another relativistic effect is the 'spin-orbit splitting' for p, d and f orbitals into j = 1 ± 1/2 states. Where j is the total angular momentum vector and 1 is angular quantum number. All of these effects have the same order of magnitude and increase roughly according to Z. This feature is what makes studying the heavy elements so interesting because the chemical properties of transactinide elements should strongly exhibit these effects. For this work the terms heavy element and transactinide elements will be used interchangeably and are defined as elements with an atomic number greater than 103, Z> 103. In order to study the transactinide elements they must be isolated once they have been produced and transported to a chemistry apparatus. The transactinide elements are produced either via 'hot' or 'cold' fusion reactions. 'Hot' fusion reactions result in excitation energies of the compound nucleus of 40-50 MeV and occur when an actinide target nuclei fuse with a projectile with A 40, where A is the atomic mass number. 'Cold' fusion results in excitation energies of 10-15 MeV. Cold fusion conditions tend to occur when a target of a spherical nuclei (Pb or Bi) is bombarded with a heavy projectile (A 40). Hot fusion generally leads to neutron rich isotopes and cold fusion tends to produce a compound nucleus that emits 1-2 neutrons upon de-excitation. If a sufficiently thin target is employed, then the products of the nuclear reaction will recoil out of the target and can either be transported to the chemistry setup, e.g. using a gas jet, or trapped by implementing them on a catcher. An example for a catcher setup using a copper block as a catcher is described here. The copper block is placed behind the target during the irradiation and all nuclei recoiling from the target position will implant themselves in the block. The copper block is subsequently dismounted and sputter cleaned. It is then shaved with a micro-lathe. The 7-10 [mu]m copper shavings are then subjected to chemical separation. The copper is dissolved in aqua regia. Lanthanum carrier is added to the aqua regia to precipitate tri-, tetra- and penta- valent cations when ammonium hydroxide is added. The precipitate is then washed and converted to the nitrate form. This solution is then added onto a cation exchange column, the eluent is deposited and dried on a polypropylene film and then counted on solid state detectors. There are several challenges when studying the chemical behavior of transactinide elements. The first challenge is the low production rate of transactinides. Transactinides are produced on an atom-at-a-time basis, meaning that only one atom is ever available for chemical study. Because of this the chemical system being used must be selective for only one chemical state. The second challenge in transactinide chemistry is the short half-lives of the elements. Half-lives of the transactinides range from nanoseconds to a few hours. This leads to the need for fast chemistry. Another challenge is the need for a high degree of separation from interfering radionuclides so that the event with the transactinide element can be detected.

Neutron Radiative Capture

Author : B. J. Allen
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Neutron Physics and Nuclear Data in Science and Technology, Volume 3: Neutron Radiative Capture discusses topics that help bridge the gap between experimental and theoretical scientists and applications scientists and engineers. The first chapter discusses the theory of slow neutron radiative capture, while the second chapter covers fast neutron radiative capture. Chapter III talks about methods for calculating neutron capture cross sections and gamma-ray spectra, while Chapter IV deals with the measurement techniques for radiative neutron capture, and Chapter V discusses neutron capture proce.

Journal of Glenn T Seaborg 1971 1979

Author : Glenn Theodore Seaborg
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Relativistic Theory of Atoms and Molecules 1993 1999

Author : Pekka Pyykkö
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Relativistic Effects in Heavy Element Chemistry and Physics

Author : Hess
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Heavy atoms and their compounds are important in many areas of modern technology. Their versatility in the reactions they undergo is the reason that they can be found in most homogeneous and heterogeneous catalysts. Their magnetism is the decisive property that qualifies them as materials for modern storage devices. The phenomena observed in compounds of heavy atoms such as phosphorescence, magnetism or the tendency for high valency in chemical reactions can to a large extent be traced back to relativistic effects in their electronic structure. Thus, in many respects relativistic effects dominate the physics and chemistry of heavy atoms and their compounds. Chemists are usually aware of these phenomena. However, the theory behind them is not part of the standard chemistry curriculum and thus not widely known among experimentalists. Whilst the relativistic quantum theory of electronic structure is well established in physics, applications of the theory to chemical systems and materials have been feasible only in the last decade and their practical applications in connection with chemical experiment is somewhat out of sight of modern theoretical physics. Relativistic Effects in Heavy Element Chemistry and Physics intends to bridge the gap between chemistry and physics on the one hand and theory and experiment on the other. Topics covered include: - A broad range from quantum electrodynamics to the phenomenology of the compounds of heavy and superheavy elements; - A state-of-the-art survey of the most important theoretical developments and applications in the field of relativistic effects in heavy-element chemistry and physics in the last decade; - Special emphasis on the work of researchers in Europe and Germany in the framework of research programmes of the European Science Foundation and the German Science Foundation.

Energy Research Abstracts

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Includes all works deriving from DOE, other related government-sponsored information and foreign nonnuclear information.

Chemical Aspects of the Atomic Nucleus

Author : J. G. Cuninghame
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This monograph gives essentials of nuclear physics, followed by structure analysis, analytical chemistry and general inorganic chemistry.

Russian Journal of Inorganic Chemistry

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Lanthanide and Actinide Chemistry

Author : Simon Cotton
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This series reflects the pivotal role of modern inorganic and physical chemistry in a range of emerging areas and in this text, the main features of the Lanthanides, Actinides and the Transactinide elements are described, enabling clear comparison and contrast with the Transition elements and Main Group metals.

The Chemistry of Superheavy Elements

Author : Matthias Schädel
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The second edition of "The Chemistry of the Superheavy Elements" provides a complete coverage of the chemistry of a series of elements beginning with atomic number 104 – the transactinides or superheavy elements – including their nuclear properties and production in nuclear reactions at heavy-ion accelerators. The contributors to this work include many renowned scientists who, during the last decades, have made vast contributions towards understanding the physics and chemistry of these elusive elements, both experimentally and theoretically. The main emphasis here is on demonstrating the fascinating studies involved in probing the architecture of the Periodic Table at its uppermost end, where relativistic effects drastically influence chemical properties. All known chemical properties of these elements are described together with the experimental techniques applied to study these short-lived man-made elements one atom-at-a-time. The status of theoretical chemistry and of empirical models is presented as well as aspects of nuclear physics. In addition, one chapter outlines the meanderings in this field from a historical perspective and the search for superheavy elements in Nature.

Kirk Othmer Encyclopedia of Chemical Technology Volume 1

Author : Kirk-Othmer
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The fifth edition of the Kirk-Othmer Encyclopedia of Chemical Technology builds upon the solid foundation of the previous editions, which have proven to be a mainstay for chemists, biochemists, and engineers at academic, industrial, and government institutions since publication of the first edition in 1949. The new edition includes necessary adjustments and modernisation of the content to reflect changes and developments in chemical technology. Presenting a wide scope of articles on chemical substances, properties, manufacturing, and uses; on industrial processes, unit operations in chemical engineering; and on fundamentals and scientific subjects related to the field. The Encyclopedia describes established technology along with cutting edge topics of interest in the wide field of chemical technology, whilst uniquely providing the necessary perspective and insight into pertinent aspects, rather than merely presenting information. * Set begins publication in March 2004 * Over 1000 articles in 27 volumes * More than 600 new or updated articles Reviews from the previous edition: "The most indispensable reference in the English language on all aspects of chemical technology...the best reference of its kind". Chemical Engineering News, 1992 "Overall, ECT is well written and cleanly edited, and no library claiming to be a useful resource for chemical engineering professionals should be without it." Nicholas Basta, Chemical Engineering, December 1992

Euro Abstracts

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The Chemistry of the Actinide and Transactinide Elements Set Vol 1 6

Author : L.R. Morss
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The fourth edition of "The Chemistry of the Actinide and Transactinide Elements" comprises all chapters in volumes 1 through 5 of the third edition (published in 2006) plus a new volume 6. To remain consistent with the plan of the first edition, “ ... to provide a comprehensive and uniform treatment of the chemistry of the actinide [and transactinide] elements for both the nuclear technologist and the inorganic and physical chemist,” and to be consistent with the maturity of the field, the fourth edition is organized in three parts. The first group of chapters follows the format of the first and second editions with chapters on individual elements or groups of elements that describe and interpret their chemical properties. A chapter on the chemical properties of the transactinide elements follows. The second group, chapters 15-26, summarizes and correlates physical and chemical properties that are in general unique to the actinide elements, because most of these elements contain partially-filled shells of 5f electrons whether present as isolated atoms or ions, as metals, as compounds, or as ions in solution. The third group, chapters 27-39, focuses on specialized topics that encompass contemporary fields related to actinides in the environment, in the human body, and in storage or wastes. Two appendices at the end of volume 5 tabulate important nuclear properties of all actinide and transactinide isotopes. Volume 6 (Chapters 32 through 39) consists of new chapters that focus on actinide species in the environment, actinide waste forms, nuclear fuels, analytical chemistry of plutonium, actinide chalcogenide and hydrothermal synthesis of actinide compounds. The subject and author indices and list of contributors encompass all six volumes.