The Chemical Complexities of Plutonium David L
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Modeling the Shape of Ions in Pyrite-Type Crystals
Crystals 2014, 4, 390-403; doi:10.3390/cryst4030390 OPEN ACCESS crystals ISSN 2073-4352 www.mdpi.com/journal/crystals Article Modeling the Shape of Ions in Pyrite-Type Crystals Mario Birkholz IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany; E-Mail: [email protected]; Tel.: +49-335-56250 Received: 13 April 2014; in revised form: 22 August 2014 / Accepted: 26 August 2014 / Published: 3 September 2014 Abstract: The geometrical shape of ions in crystals and the concept of ionic radii are re-considered. The re-investigation is motivated by the fact that a spherical modelling is justified for p valence shell ions on cubic lattice sites only. For the majority of point groups, however, the ionic radius must be assumed to be an anisotropic quantity. An appropriate modelling of p valence ions then has to be performed by ellipsoids. The approach is tested for pyrite-structured dichalcogenides MX2, with chalcogen ions X = O, S, Se and Te. The latter are found to exhibit the shape of ellipsoids being compressed along the <111> symmetry axes, with two radii r|| and describing their spatial extension. Based on this ansatz, accurate interatomic M–X distances can be derived and a consistent geometrical model emerges for pyrite-structured compounds. Remarkably, the volumes of chalcogen ions are found to vary only little in different MX2 compounds, suggesting the ionic volume rather than the ionic radius to behave as a crystal-chemical constant. Keywords: ionic radius; ionic shape; bonding distance; ionic volume; pyrite-type compounds; di-chalcogenides; di-oxides; di-sulfides; di-selenides; di-tellurides 1. -
Chapter 7 Electron Configuration and the Periodic Table
Chapter 7 Electron Configuration and the Periodic Table Copyright McGraw-Hill 2009 1 7.1 Development of the Periodic Table • 1864 - John Newlands - Law of Octaves- every 8th element had similar properties when arranged by atomic masses (not true past Ca) • 1869 - Dmitri Mendeleev & Lothar Meyer - independently proposed idea of periodicity (recurrence of properties) Copyright McGraw-Hill 2009 2 • Mendeleev – Grouped elements (66) according to properties – Predicted properties for elements not yet discovered – Though a good model, Mendeleev could not explain inconsistencies, for instance, all elements were not in order according to atomic mass Copyright McGraw-Hill 2009 3 • 1913 - Henry Moseley explained the discrepancy – Discovered correlation between number of protons (atomic number) and frequency of X rays generated – Today, elements are arranged in order of increasing atomic number Copyright McGraw-Hill 2009 4 Periodic Table by Dates of Discovery Copyright McGraw-Hill 2009 5 Essential Elements in the Human Body Copyright McGraw-Hill 2009 6 The Modern Periodic Table Copyright McGraw-Hill 2009 7 7.2 The Modern Periodic Table • Classification of Elements – Main group elements - “representative elements” Group 1A- 7A – Noble gases - Group 8A all have ns2np6 configuration(exception-He) – Transition elements - 1B, 3B - 8B “d- block” – Lanthanides/actinides - “f-block” Copyright McGraw-Hill 2009 8 Periodic Table Colored Coded By Main Classifications Copyright McGraw-Hill 2009 9 Copyright McGraw-Hill 2009 10 • Predicting properties – Valence -
Chemistry – Inorganic Chemistry
Answer on Question #53306 – Chemistry – Inorganic Chemistry Question What is oxidation state? How can find out the oxidation state of particular element? Explain its trend in the group and period, give reasons Answer The oxidation state is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. The oxidation state, which may be positive, negative or equal to zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were completely ionic, with no covalent component. To find out the oxidation state of particular element one should use some simple rules: 1. The oxidation state of an element in a simple substance (for example, He or Cl2, or Fe, or C, or whatever containing one type of atoms) is equal to zero. 2. The sum of the oxidation states of all the atoms or ions in a neutral compound is zero. 3. The sum of the oxidation states of all the atoms in an ion is equal to the charge on the ion. 4. The more electronegative element in a substance is given a negative oxidation state. The less electronegative one is given a positive oxidation state. 5. Some elements almost always have the same oxidation states in their compounds: Element Oxidation state Group 1 metals (Li, Na, K, Rb, Cs, Fr) always +1 Group 2 metals (Be, Mg, Ca, Sr, Ba, Ra) always +2 Fluorine (F) always -1 Oxygen (O) usually -2 (except in peroxides (-1) and F2O (+2)) Hydrogen (H) usually +1 (except in metal hydrides (-1)) Having known the oxidation states of these elements in the compound and having known the rule 3, the oxidation state of particular element can be found. -
A Study of the Hydration of the Alkali Metal Ions in Aqueous Solution
Article pubs.acs.org/IC A Study of the Hydration of the Alkali Metal Ions in Aqueous Solution Johan Mahler̈ and Ingmar Persson* Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden *S Supporting Information ABSTRACT: The hydration of the alkali metal ions in aqueous solution has been studied by large angle X-ray scattering (LAXS) and double difference infrared spectroscopy (DDIR). The structures of the dimethyl sulfoxide solvated alkali metal ions in solution have been determined to support the studies in aqueous solution. The results of the LAXS and DDIR mea- surements show that the sodium, potassium, rubidium and cesium ions all are weakly hydrated with only a single shell of water molecules. The smaller lithium ion is more strongly hydrated, most probably with a second hydration shell present. The influence of the rubidium and cesium ions on the water structure was found to be very weak, and it was not possible to quantify this effect in a reliable way due to insufficient separation of the O−D stretching bands of partially deuterated water bound to these metal ions and the O−D stretching bands of the bulk water. Aqueous solutions of sodium, potassium and cesium iodide and cesium and lithium hydroxide have been studied by LAXS and M−O bond distances have been determined fairly accurately except for lithium. However, the number of water molecules binding to the alkali metal ions is very difficult to determine from the LAXS measurements as the number of distances and the temperature factor are strongly correlated. -
Catalytic Organic Transformations Mediated by Actinide Complexes
Inorganics 2015, 3, 392-428; doi:10.3390/inorganics3040392 OPEN ACCESS inorganics ISSN 2304-6740 www.mdpi.com/journal/inorganics Review Catalytic Organic Transformations Mediated by Actinide Complexes Isabell S. R. Karmel, Rami J. Batrice and Moris S. Eisen * Schulich Faculty of Chemistry, Technion—Israel Institute of Technology, Technion City, Haifa 32000, Israel; E-Mails: [email protected] (I.S.R.K.); [email protected] (R.J.B.) * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel./Fax: +972-4-829-2680. Academic Editors: Stephen Mansell and Steve Liddle Received: 16 September 2015 / Accepted: 9 October 2015 / Published: 30 October 2015 Abstract: This review article presents the development of organoactinides and actinide coordination complexes as catalysts for homogeneous organic transformations. This chapter introduces the basic principles of actinide catalysis and deals with the historic development of actinide complexes in catalytic processes. The application of organoactinides in homogeneous catalysis is exemplified in the hydroelementation reactions, such as the hydroamination, hydrosilylation, hydroalkoxylation and hydrothiolation of alkynes. Additionally, the use of actinide coordination complexes for the catalytic polymerization of α-olefins and the ring opening polymerization of cyclic esters is presented. The last part of this review article highlights novel catalytic transformations mediated by actinide compounds and gives an outlook to the further potential of this field. Keywords: organoactinides; actinide coordination complexes; homogeneous catalysis; hydroelementations; polymerization of olefins; ROP; activation of heterocumulenes 1. Introduction The beginning of modern organoactinide chemistry is often attributed to the synthesis of 8 uranocene, [(η -C8H8)2U] in 1968, as the analogous compound to ferrocene and other transition metal metallocenes [1,2]. -
Electron Configuration Example Script
Electron Configuration Example Script This video demonstrates how to write electron configurations and draw orbital diagrams for main group elements. To write an electron configuration you could memorize the order in which orbitals are filled according to their energy level, but a more convenient method is to use the periodic table. The periodic table is arranged in blocks, each block represents an orbital, and each space in the block counts as one electron. The s block is the first two left-hand columns of the periodic table and includes helium. The p block is the last six columns on the right hand side stating at boron. The d block is the transition metals in the middle of the periodic table, and the f block is the lanthanide and actinide series. To begin start at the top left hand corner of the periodic table and work your way down by reading across a row from left to right and filling in the proper amount of electrons for each orbital until you reach your element. Use the number assigned to each row, 1 thru 7, as the value of the principle quantum number n, when you arrive at the d and f blocks; subtract one from the n value for the d orbitals, and two from the n value for the f orbitals. This periodic table has the electron configuration for each row written along the left hand side using the method just outlined. Let’s use it to write the electron configuration of a neutral bromine atom, a bromine atom has 35 electrons. -
Atomic and Ionic Radii of Elements 1–96 Martinrahm,*[A] Roald Hoffmann,*[A] and N
DOI:10.1002/chem.201602949 Full Paper & Elemental Radii Atomic and Ionic Radii of Elements 1–96 MartinRahm,*[a] Roald Hoffmann,*[a] and N. W. Ashcroft[b] Abstract: Atomic and cationic radii have been calculated for tive measureofthe sizes of non-interacting atoms, common- the first 96 elements, together with selected anionicradii. ly invoked in the rationalization of chemicalbonding, struc- The metric adopted is the average distance from the nucleus ture, and different properties. Remarkably,the atomic radii where the electron density falls to 0.001 electrons per bohr3, as defined in this way correlate well with van der Waals radii following earlier work by Boyd. Our radii are derived using derived from crystal structures. Arationalizationfor trends relativistic all-electron density functional theory calculations, and exceptionsinthose correlations is provided. close to the basis set limit. They offer asystematic quantita- Introduction cule,[2] but we prefer to follow through with aconsistent pic- ture, one of gauging the density in the atomic groundstate. What is the size of an atom or an ion?This question has been The attractivenessofdefining radii from the electron density anatural one to ask over the centurythat we have had good is that a) the electron density is, at least in principle, an experi- experimental metricinformation on atoms in every form of mental observable,and b) it is the electron density at the out- matter,and (more recently) reliable theory for thesesame ermost regionsofasystem that determines Pauli/exchange/ atoms. And the momentone asks this question one knows same-spinrepulsions, or attractive bondinginteractions, with that there is no unique answer.Anatom or ion coursing down achemical surrounding. -
Electron Configurations, Orbital Notation and Quantum Numbers
5 Electron Configurations, Orbital Notation and Quantum Numbers Electron Configurations, Orbital Notation and Quantum Numbers Understanding Electron Arrangement and Oxidation States Chemical properties depend on the number and arrangement of electrons in an atom. Usually, only the valence or outermost electrons are involved in chemical reactions. The electron cloud is compartmentalized. We model this compartmentalization through the use of electron configurations and orbital notations. The compartmentalization is as follows, energy levels have sublevels which have orbitals within them. We can use an apartment building as an analogy. The atom is the building, the floors of the apartment building are the energy levels, the apartments on a given floor are the orbitals and electrons reside inside the orbitals. There are two governing rules to consider when assigning electron configurations and orbital notations. Along with these rules, you must remember electrons are lazy and they hate each other, they will fill the lowest energy states first AND electrons repel each other since like charges repel. Rule 1: The Pauli Exclusion Principle In 1925, Wolfgang Pauli stated: No two electrons in an atom can have the same set of four quantum numbers. This means no atomic orbital can contain more than TWO electrons and the electrons must be of opposite spin if they are to form a pair within an orbital. Rule 2: Hunds Rule The most stable arrangement of electrons is one with the maximum number of unpaired electrons. It minimizes electron-electron repulsions and stabilizes the atom. Here is an analogy. In large families with several children, it is a luxury for each child to have their own room. -
Diphosphazide-Supported Trialkyl Thorium(IV) Complex Tara K
pubs.acs.org/Organometallics Communication Diphosphazide-Supported Trialkyl Thorium(IV) Complex Tara K. K. Dickie, Ashraf A. Aborawi, and Paul G. Hayes* Cite This: Organometallics 2020, 39, 2047−2052 Read Online ACCESS Metrics & More Article Recommendations *sı Supporting Information ABSTRACT: The potassium salt of a new ligand, KLP=N3 (2, κ5 i i − LP=N3 = -2,5-[(4- PrC6H4)N3 P Pr2]2N(C4H2) ), that features two units of the rare phosphazide (RN3 PR3) functionality was synthesized via an incomplete Staudinger reaction between K[2,5- i i ( Pr2P)2N(C4H2)] (1)and4-PrC6H4N3. The diphosphazide ligand was transferred to a thorium(IV) metal center using salt metathesis strategies, yielding LP=N3ThCl3 (3), which contains two intact and coordinated phosphazides. Reaction of complex 3 with 3 equiv of LiCH2SiMe3 resulted in formation of the trialkyl thorium species LP=N3Th(CH2SiMe3)3 (4). In contrast, attempts to synthesize an organothorium complex supported by the previously κ3 reported bisphosphinimine ligand LP=N (LP=N = -2,5- i i − ff [(4- PrC6H4)N P Pr2]2N(C4H2) )aorded the cyclometalated * * κ4 i i i i 2− dialkyl complex L P=NTh(CH2SiMe3)2 (6,L PN = -2-[(4- PrC6H3)N P Pr2]-5-[(4- PrC6H4)N P Pr2]N(C4H2) ) and 1 equiv of free tetramethylsilane. 1 he Staudinger reaction, discovered in 1919, introduced the facile loss of N2, and, accordingly, were overlooked as ′ ’ T the formation of a phosphinimine group (R3P NR ) via viable functional groups in ligand design. Since Staudinger s the reaction of a tertiary phosphine (R3P) with an organic original work, multiple methods have been developed to ′ azide (N3R ), resulting in concomitant loss of N2. -
Electron Configuration, and Element No.155 of the Periodic Table of Elements
April, 2011 PROGRESS IN PHYSICS Volume 2 Electron Configuration, and Element No.155 of the Periodic Table of Elements Albert Khazan E-mail: [email protected] Blocks of the Electron Configuration in the atom are considered with taking into ac- count that the electron configuration should cover also element No.155. It is shown that the electron configuration formula of element No.155, in its graphical representation, completely satisfies Gaussian curve. 1 Introduction K L M N O Sum Content in the shells As is known, even the simpliests atoms are very complicate s 2 2 in each shell systems. In the centre of such a system, a massive nucleus p 2 6 8 in each, commencing is located. It consists of protons, the positively charged par- in the 2nd shell ticles, and neutrons, which are charge-free. Masses of pro- d 2 6 10 18 in each, commencing tons and neutrons are almost the same. Such a particle is in the 3rd shell almost two thousand times heavier than the electron. Charges f 2 6 10 14 32 in each, commencing of the proton and the electron are opposite, but the same in in the 4th shell the absolute value. The proton and the neutron differ from g 2 6 10 14 18 50 in each, commencing the viewpoint on electromagnetic interactions. However in in the 5th shell the scale of atomic nuclei they does not differ. The electron, the proton, and the neutron are subatomic articles. The theo- Table 1: Number of electrons in each level. retical physicists still cannot solve Schrodinger’s¨ equation for the atoms containing two and more electrons. -
Summaries of FY 1997 Research in the Chemical Sciences
DOE/NBM-1098 Rev.-1 September 1997 T O EN FE TM N R E A R P G E Y D U • • A N C I I T R E D E M ST A ATES OF Summaries of FY 1997 Research in the Chemical Sciences U.S. Department of Energy Office of Energy Research Division of Chemical Sciences A searchable version of this summary book is available at the following web address: http://websrv.er.doe.gov/asp/search.asp This search tool is also accessible from the Chemical Sciences web page at: http://www.er.doe.gov/production/bes/chm/chmhome.html Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; prices available from (423) 576-8401 Available to the public from the U.S. Department of Commerce, Technology Administration, National Technical Information Service, Springfield, VA 22161 This document was produced under contract number DE-AC05-76OR00033 between the U.S. Department of Energy and Oak Ridge Associated Universities. ORISE 97-1555 CONTENTS CONTENTS PREFACE ........................................................................ vii Oak Ridge National Laboratory.............................. 42 DIVISION OF CHEMICAL SCIENCES ..................... viii Pacific Northwest National Laboratory .................. 44 PROGRAM DESCRIPTIONS ........................................ ix Heavy Element Chemistry ....................................... 45 LABORATORY ADMINISTRATION ......................... xiii Argonne National Laboratory ................................. 45 Lawrence Berkeley National Laboratory............... -
Lawrence Berkeley Laboratory· UNIVERSITY of CALIFORNIA'
LBL-37435 UC-800 Lawrence Berkeley Laboratory· UNIVERSITY OF CALIFORNIA' To be published as a chapter in Frontiers in Nuclear Chemistry, D.D. Sood, Ed., Indian Association of Nuclear Chemists and Allied Scientists, Bombay, India, 1995 Summary of the Properties of the Lanthanide and Actinide Elements G.T. Seaborg and D.E. Hobart June 1995 --- :0 I'T1 ..(") em'"T1 -,o::c oCDm S::III:Z _. (") QI:ZI'T1 r+~(") CD 0 "'0 CD_. -< c.--- CQ. r t:Dr- 1 w...... ~ w U1 Prepared for the U.S. Department of Energy under Contract Number DE-AC03-76SF00098 DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United .States Government nor any agency thereof, nor The Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately ()wned rights. Reference he~ein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or The Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof, or The Regents of the University of California.