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2 Literature Review
2 Literature review 2.1 Thin film solid state reactions A solid state chemical reaction in the classical sense occurs when local transport of matter is observed in crystalline phases and new phases are formed.1 This definition does not mean that gaseous or liquid phases may not take part in the solid state reactions. However, it does mean that the reaction product occurs as a solid phase. Thus, the tarnishing of metals during dry or wet oxidation is also considered to be a solid state reaction. Commonly, the solid state reac- tions are heterogeneous reactions. If after reaction of two substances one or more solid product phases are formed, then a heterogeneous solid state reaction is said to have occurred. Spinel- and pyrochlore-forming reactions are well-known examples of solid-state reactions where a ternary oxide forms.5–11 In this Ph.D. thesis, heterogeneous solid state reactions are considered. Extended crystal defects as high mobility paths for atoms are essential in the reactivity of solids. Furthermore, interfaces play an important role in the solid state reactions because during hetero- geneous reactions interfaces move and mass transport occurs across them. The interfaces can be coherent, semicoherent or incoherent.28 At the interface, chemical reactions take place between species and defects; they are often associated with structural transformations and volume changes. The characteristics of thin film solid state reactions running on the nanometer scale are con- siderably different from solid state reactions proceeding in the bulk. During bulk reactions, the diffusion process is rate limiting and controls the growth. -
The Radiochemistry of Beryllium
National Academy of Sciences National Research Council I NUCLEAR SCIENCE SERIES The Radiochemistry ·of Beryllium COMMITTEE ON NUCLEAR SCIENCE L. F. CURTISS, Chairman ROBLEY D. EVANS, Vice Chairman National Bureau of Standards MassaChusetts Institute of Technol0gy J. A. DeJUREN, Secretary ./Westinghouse Electric Corporation H.J. CURTIS G. G. MANOV Brookhaven National' LaboratOry Tracerlab, Inc. SAMUEL EPSTEIN W. WAYNE MEINKE CalUornia Institute of Technology University of Michigan HERBERT GOLDSTEIN A.H. SNELL Nuclear Development Corporation of , oak Ridge National Laboratory America E. A. UEHLING H.J. GOMBERG University of Washington University of Michigan D. M. VAN PATTER E.D.KLEMA Bartol Research Foundation Northwestern University ROBERT L. PLATZMAN Argonne National Laboratory LIAISON MEMBERS PAUL C .. AEBERSOLD W.D.URRY Atomic Energy Commission U. S. Air Force J. HOW ARD McMILLEN WILLIAM E. WRIGHT National Science Foundation Office of Naval Research SUBCOMMITTEE ON RADIOCHEMISTRY W. WAYNE MEINKE, Chairman HAROLD KIRBY University of Michigan Mound Laboratory GREGORY R. CHOPPIN GEORGE LEDDICOTTE Florida State University. Oak Ridge National Laboratory GEORGE A. COW AN JULIAN NIELSEN Los Alamos Scientific Laboratory Hanford Laboratories ARTHUR W. FAIRHALL ELLIS P. STEINBERG University of Washington Argonne National Laboratory JEROME HUDIS PETER C. STEVENSON Brookhaven National Laboratory University of California (Livermore) EARL HYDE LEO YAFFE University of CalUornia (Berkeley) McGill University CONSULTANTS NATHAN BALLOU WILLIAM MARLOW Naval Radiological Defense Laboratory N atlonal Bureau of Standards JAMESDeVOE University of Michigan CHF.MISTRY-RADIATION AND RADK>CHEMIST The Radiochemistry of Beryllium By A. W. FAIRHALL. Department of Chemistry University of Washington Seattle, Washington May 1960 ' Subcommittee on Radiochemistry National Academy of Sciences - National Research Council Printed in USA. -
Iron-Catalysed Transformation of Molecular Dinitrogen Into Silylamine Under Ambient Conditions
ARTICLE Received 6 Sep 2012 | Accepted 6 Nov 2012 | Published 4 Dec 2012 DOI: 10.1038/ncomms2264 Iron-catalysed transformation of molecular dinitrogen into silylamine under ambient conditions Masahiro Yuki1, Hiromasa Tanaka2, Kouitsu Sasaki1, Yoshihiro Miyake1, Kazunari Yoshizawa2 & Yoshiaki Nishibayashi1 Although stoichiometric transformations using transition metal–N2 complexes have been well investigated towards the goal of nitrogen fixation under mild reaction conditions, only a few examples of the catalytic transformations of N2 using transition metal–N2 complexes as catalysts have been reported. In almost all the catalytic systems, the use of Mo is essential to realize the catalytic transformation of N2, where Mo–N2 complexes are considered to work as effective catalysts. Here we show the first successful example of the Fe-catalysed transfor- mation of N2 into N(SiMe3)3 under ambient conditions, in which iron complexes such as iron pentacarbonyl [Fe(CO)5] and ferrocenes have been found to work as effective catalysts. A plausible reaction pathway is proposed, where Fe(II)–N2 complex bearing two Me3Si groups as ancillary ligands has an important role as a key reactive intermediate, with the aid of density-functional-theory calculations. 1 Institute of Engineering Innovation, School of Engineering, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan. 2 Institute for Materials Chemistry and Engineering, International Research Center for Molecular Systems, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan. Correspondence and requests for materials should be addressed to K.Y. (email: [email protected]) or to Y.N. (email: [email protected]). -
Perovskites: Crystal Structure, Important Compounds and Properties
Perovskites: crystal structure, important compounds and properties Peng Gao GMF Group Meeting 12,04,2016 Solar energy resource PV instillations Global Power Demand Terrestrial sun light To start • We have to solve the energy problem. • Any technology that has good potential to cut carbon emissions by > 10 % needs to be explored aggressively. • Researchers should not be deterred by the struggles some companies are having. • Someone needs to invest in scaling up promising solar cell technologies. Origin And History of Perovskite compounds Perovskite is calcium titanium oxide or calcium titanate, with the chemical formula CaTiO3. The mineral was discovered by Gustav Rose in 1839 and is named after Russian mineralogist Count Lev Alekseevich Perovski (1792–1856).” All materials with the same crystal structure as CaTiO3, namely ABX3, are termed perovskites: Origin And History of Perovskite compounds Very stable structure, large number of compounds, variety of properties, many practical applications. Key role of the BO6 octahedra in ferromagnetism and ferroelectricity. Extensive formation of solid solutions material optimization by composition control and phase transition engineering. A2+ B4+ O2- Ideal cubic perovskite structure (ABO3) Classification of Perovskite System Perovskite Systems Inorganic Halide Oxide Perovskites Perovskites Alkali-halide Organo-Metal Intrinsic Doped Perovskites Halide Perovskites Perovskites A2Cl(LaNb2)O7 Perovskites 1892: 1st paper on lead halide perovskites Structure deduced 1959: Kongelige Danske Videnskabernes -
Structure Refinement of Polycrystalline Orthorhombic Yttrium Substituted Calcium Titanate: Ca1−Xyxtio3+Δ (X = 0·1–0·3)
Bull. Mater. Sci., Vol. 34, No. 1, February 2011, pp. 89–95. c Indian Academy of Sciences. Structure refinement of polycrystalline orthorhombic yttrium substituted calcium titanate: Ca1−xYxTiO3+δ (x = 0·1–0·3) RASHMI CHOURASIA and O P SHRIVASTAVA∗ Department of Chemistry, Dr H.S. Gour University, Sagar 470 003, India MS received 23 May 2007; revised 7 September 2010 Abstract. The perovskite ceramic phases with composition Ca1−xYxTiO3+δ (where x = 0·1, 0·2and0·3; hereafter CYT-10, CYT-20 and CYT-30) have been synthesized by solid state reaction at 1050◦C. The structure refinement using general structure analysis system (GSAS) software converges to satisfactory profile indicators such as Rietveld 2 parameters: Rp, Rwp,RF and goodness of fit. The title phases crystallize at room temperature in the space group Pbnm (#62) with a = 5·3741(4) Å, b = 5·4300(4) Å, c = 7·6229(5) Å and Z = 4. Major interatomic distances, bond angles and structure factors have been calculated from the step analysis data of the compound. The crys- tal morphology has been examined by scanning electron microscopy. Energy dispersive X-ray (EDX) analysis of the specimens show that yttrium enters into the structural framework of CaTiO3. The particle size of the ceramic phases along major reflection planes ranges between 12 and 40 nm. The polyhedral (CaO8 and TiO6) distortions and valence calculations from bond strength data are also reported. Keywords. Perovskites; powder X-ray diffraction; Rietveld refinement; GSAS; nanoceramic. 1. Introduction 2. Experimental Perovskite type oxides of general formula ABO3 are well 2.1 Ceramic route synthesis of Ca1−x Yx TiO3 (x = 0·1–0·3) known for their property of cationic substitution on A site phases (Goodenough et al 1976; Myhra et al 1986; Ringwood 1985; Shrivastava and Shrivastava 2002). -
Combustion Synthesis, Sintering, Characterization, and Properties
Hindawi Advances in Materials Science and Engineering Volume 2019, Article ID 9639016, 9 pages https://doi.org/10.1155/2019/9639016 Research Article Calcium Titanate from Food Waste: Combustion Synthesis, Sintering, Characterization, and Properties Siriluk Cherdchom,1 Thitiwat Rattanaphan,1 and Tawat Chanadee 1,2 1Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University (PSU), Hat Yai, Songkhla 90110, &ailand 2Ceramic and Composite Materials Engineering Research Group (CMERG), Center of Excellence in Materials Engineering (CEME), Prince of Songkla University (PSU), Hat Yai, Songkhla 90110, &ailand Correspondence should be addressed to Tawat Chanadee; [email protected] Received 31 August 2018; Revised 20 December 2018; Accepted 3 January 2019; Published 12 February 2019 Academic Editor: Andres Sotelo Copyright © 2019 Siriluk Cherdchom et al. )is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Calcium titanate (CaTiO3) was combustion synthesized from a calcium source of waste duck eggshell, anatase titanium dioxide (A-TiO2), and magnesium (Mg). )e eggshell and A-TiO2 were milled for 30 min in either a high-energy planetary mill or a conventional ball mill. )ese powders were then separately mixed with Mg in a ball mill. After synthesis, the combustion products were leached and then sintered to produce CaTiO3 ceramic. Analytical characterization of the as-leached combustion products revealed that the product of the combustion synthesis of duck eggshell + A-TiO2 that had been high-energy-milled for 30 min before synthesis comprised a single perovskite phase of CaTiO3. -
Organometrallic Chemistry
CHE 425: ORGANOMETALLIC CHEMISTRY SOURCE: OPEN ACCESS FROM INTERNET; Striver and Atkins Inorganic Chemistry Lecturer: Prof. O. G. Adeyemi ORGANOMETALLIC CHEMISTRY Definitions: Organometallic compounds are compounds that possess one or more metal-carbon bond. The bond must be “ionic or covalent, localized or delocalized between one or more carbon atoms of an organic group or molecule and a transition, lanthanide, actinide, or main group metal atom.” Organometallic chemistry is often described as a bridge between organic and inorganic chemistry. Organometallic compounds are very important in the chemical industry, as a number of them are used as industrial catalysts and as a route to synthesizing drugs that would not have been possible using purely organic synthetic routes. Coordinative unsaturation is a term used to describe a complex that has one or more open coordination sites where another ligand can be accommodated. Coordinative unsaturation is a very important concept in organotrasition metal chemistry. Hapticity of a ligand is the number of atoms that are directly bonded to the metal centre. Hapticity is denoted with a Greek letter η (eta) and the number of bonds a ligand has with a metal centre is indicated as a superscript, thus η1, η2, η3, ηn for hapticity 1, 2, 3, and n respectively. Bridging ligands are normally preceded by μ, with a subscript to indicate the number of metal centres it bridges, e.g. μ2–CO for a CO that bridges two metal centres. Ambidentate ligands are polydentate ligands that can coordinate to the metal centre through one or more atoms. – – – For example CN can coordinate via C or N; SCN via S or N; NO2 via N or N. -
Chemical Intercalation of Zerovalent Metals Into 2D Layered Bi2se3 Nanoribbons † † ‡ † † † § Kristie J
Article pubs.acs.org/JACS Chemical Intercalation of Zerovalent Metals into 2D Layered Bi2Se3 Nanoribbons † † ‡ † † † § Kristie J. Koski, Colin D. Wessells, Bryan W. Reed, Judy J. Cha, Desheng Kong, and Yi Cui*, , † Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States ‡ Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States § SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, United States *S Supporting Information ABSTRACT: We have developed a chemical method to intercalate a variety of zerovalent metal atoms into two-dimen- sional (2D) layered Bi2Se3 chalcogenide nanoribbons. We use a chemical reaction, such as a disproportionation redox reaction, to generate dilute zerovalent metal atoms in a refluxing solution, which intercalate into the layered Bi2Se3 structure. The zerovalent nature of the intercalant allows superstoichiometric intercalation of metal atoms such as Ag, Au, Co, Cu, Fe, In, Ni, and Sn. We foresee the impact of this methodology in establishing novel fundamental physical behaviors and in possible energy applications. 1. INTRODUCTION Ni, and Sn. Some interesting effects that could arise with − 7−10 intercalation are superconductivity, such as in Cu Bi2Se3, Intercalation is the insertion of a guest species into a host 6 lattice. Intercalation into layered materials is essential to battery enhanced conductivity, or possibly opening a surface state gap electrodes, electrochromics, detergents, and solid lubricants and in topological insulator Bi2Se3. This method of zerovalent metal is important in exotic fundamental two-dimensional (2D) intercalation may also be extended to other layered materials. -
Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc
Metal-Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc Richard H. Duncan Lyngdoh*,a, Henry F. Schaefer III*,b and R. Bruce King*,b a Department of Chemistry, North-Eastern Hill University, Shillong 793022, India B Centre for Computational Quantum Chemistry, University of Georgia, Athens GA 30602 ABSTRACT: This survey of metal-metal (MM) bond distances in binuclear complexes of the first row 3d-block elements reviews experimental and computational research on a wide range of such systems. The metals surveyed are titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc, representing the only comprehensive presentation of such results to date. Factors impacting MM bond lengths that are discussed here include (a) n+ the formal MM bond order, (b) size of the metal ion present in the bimetallic core (M2) , (c) the metal oxidation state, (d) effects of ligand basicity, coordination mode and number, and (e) steric effects of bulky ligands. Correlations between experimental and computational findings are examined wherever possible, often yielding good agreement for MM bond lengths. The formal bond order provides a key basis for assessing experimental and computationally derived MM bond lengths. The effects of change in the metal upon MM bond length ranges in binuclear complexes suggest trends for single, double, triple, and quadruple MM bonds which are related to the available information on metal atomic radii. It emerges that while specific factors for a limited range of complexes are found to have their expected impact in many cases, the assessment of the net effect of these factors is challenging. -
18- Electron Rule. 18 Electron Rule Cont’D Recall That for MAIN GROUP Elements the Octet Rule Is Used to Predict the Formulae of Covalent Compounds
18- Electron Rule. 18 Electron Rule cont’d Recall that for MAIN GROUP elements the octet rule is used to predict the formulae of covalent compounds. Example 1. This rule assumes that the central atom in a compound will make bonds such Oxidation state of Co? [Co(NH ) ]+3 that the total number of electrons around the central atom is 8. THIS IS THE 3 6 Electron configuration of Co? MAXIMUM CAPACITY OF THE s and p orbitals. Electrons from Ligands? Electrons from Co? This rule is only valid for Total electrons? Period 2 nonmetallic elements. Example 2. Oxidation state of Fe? The 18-electron Rule is based on a similar concept. Electron configuration of Fe? [Fe(CO) ] The central TM can accommodate electrons in the s, p, and d orbitals. 5 Electrons from Ligands? Electrons from Fe? s (2) , p (6) , and d (10) = maximum of 18 Total electrons? This means that a TM can add electrons from Lewis Bases (or ligands) in What can the EAN rule tell us about [Fe(CO)5]? addition to its valence electrons to a total of 18. It can’t occur…… 20-electron complex. This is also known Effective Atomic Number (EAN) Rule Note that it only applies to metals with low oxidation states. 1 2 Sandwich Compounds Obeying EAN EAN Summary 1. Works well only for d-block metals. It does not apply to f-block Let’s draw some structures and see some new ligands. metals. 2. Works best for compounds with TMs of low ox. state. Each of these ligands is π-bonded above and below the metal center. -
Iron Pentacarbonyl
Poison Facts: Low Chemicals: Iron Pentacarbonyl Properties of the Chemical Iron carbonyl (pentacarbonyl iron), C5FeO5, is a yellow, oily liquid. It is pyrophoric in air and burns to Fe2O3 (Iron[III] oxide) and decomposes by light to Fe2(CO)9 and CO. It is practically insoluble in water, readily soluble in most organic solvents (ether, acetone, ethyl acetate) and slightly soluble in alcohol. The vapor is heavier than air and may travel along the ground. Distant ignition is possible, and it may explode on heating. It may also spontaneously ignite in contact with air. Iron pentacarbonyl is a strong reducing agent and reacts violently with oxidants. Uses of the Chemical Iron pentacarbonyl is prepared from iron (and iron compounds) and CO. It is used in the manufacture of powdered iron cores for high-frequency coils used in the radio and television industries. It is also used as an anti-knock agent in motor fuels and as a catalyst in organic reactions. Absorption, Distribution, Metabolism and Excretion (ADME) Iron pentacarbonyl can be absorbed into the body by inhalation of the vapor, through the skin or by ingestion. No other pharmacokinetic data is available. Clinical Effects of Acute Exposure • Ocular exposures: Iron pentacarbonyl is a local irritant and may cause irritation and injury to eyes. • Dermal exposures: The chemical may irritate the skin and mucous membranes. It may be absorbed through the skin. • Inhalation exposures: If inhaled, iron pentacarbonyl is a local irritant to the lungs and gastrointestinal tract. Symptoms of acute exposure to high concentrations resemble those of exposures to nickel carbonyl. -
Electroanalytical Chemistry of Some Organometallic Compounds of Tin, Lead and Germanium
ELECTROANALYTICAL CHEMISTRY OF SOME ORGANOMETALLIC COMPOUNDS OF TIN, LEAD AND GERMANIUM by Nani Bhushan Fouzder M.Sc. (Rajshahi) A Thesis Submitted for the Degree of Doctor of Philosophy of the University of London. Chemistry Department, Imperial College of Science and Technology, London S.W.7. September, 1975. 11 ABSTRACT. The present thesis concerns the investigation into the electrochemical behaviour of some industrially important organometallic compounds of tin, lead and germanium and development of suitable electrochemical methods for the analysis of these compounds at formula- tion and at trace level. The basic principles of the electrochemical techniques used inthis investigation have been given in the first part of the 'Introduction', while the various factors which control the electrode process have been discussed in the second part of the 'Introduction' in chapter 1. The electrochemical behaviour and analytical determination of some important organotin fungicides and pesticides such as tri-n-butyltin oxide, triphenyl- tin acetate, etc., some antihelminthic compounds such as dibutyltin dilaureate and dibutyltin dimaleate and some widely used PVC-stabilizers such as di-n-Octyltin dithioglycollic acid ester (Irgastab 17 MOK), Irgastab 17M and Irgastab 15 MOR have been described in the following three chapters. For each type of compound a detailed mechanism of the electrochemical process has been proposed and established. The electrochemical behaviour of organolead compounds and of the organogermanium compounds have been described in the next three chapters. In each case, the mechanism of reduction of these compounds has been established and methods 9fc their determina- tion at ordinary and at trace level have been developed. Finally, in the eighth chapter a brief intro- duction into the highspeed liquid chromatographic technique has been given and analysis of organotin compounds by this method using a wall-jet electrode detector has been described.