Towards a Greater Understanding Of
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Vanadium Pentoxide and Other Inorganic Vanadium Compounds
This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organization, or the World Health Organization. Concise International Chemical Assessment Document 29 VANADIUM PENTOXIDE AND OTHER INORGANIC VANADIUM COMPOUNDS Note that the layout and pagination of this pdf file are not identical to the printed CICAD First draft prepared by Dr M. Costigan and Mr R. Cary, Health and Safety Executive, Liverpool, United Kingdom, and Dr S. Dobson, Centre for Ecology and Hydrology, Huntingdon, United Kingdom Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organization, and the World Health Organization, and produced within the framework of the Inter-Organization Programme for the Sound Management of Chemicals. World Health Organization Geneva, 2001 The International Programme on Chemical Safety (IPCS), established in 1980, is a joint venture of the United Nations Environment Programme (UNEP), the International Labour Organization (ILO), and the World Health Organization (WHO). The overall objectives of the IPCS are to establish the scientific basis for assessment of the risk to human health and the environment from exposure to chemicals, through international peer review processes, as a prerequisite for the promotion of chemical safety, and to provide technical assistance in strengthening national capacities for the sound management -
Toxicological Profile for Aluminum
ALUMINUM 145 4. CHEMICAL AND PHYSICAL INFORMATION 4.1 CHEMICAL IDENTITY Aluminum is a naturally occurring element that appears in the second row of Group 13 (IIIA) of the periodic table (O’Neil et al. 2001). Table 4-1 lists common synonyms and other pertinent identification information for aluminum and selected aluminum compounds. 4.2 PHYSICAL AND CHEMICAL PROPERTIES Aluminum is a silvery-white, malleable, and ductile metal. In moist air, a protective oxide coating of aluminum oxide is formed on its surface. In compounds, aluminum typically occurs in its +3 oxidation state (Lide 2005; O’Neil et al. 2001). Table 4-2 lists important physical and chemical properties of aluminum and selected aluminum compounds. ALUMINUM 146 4. CHEMICAL AND PHYSICAL INFORMATION a Table 4-1. Chemical Identity of Aluminum and Compounds Characteristic Information Chemical name Aluminum Aluminum chloride Aluminum chlorohydrate (anhydrous) Synonym(s) Aluminiumb; alumina fibre; Aluminum trichloride; Aluminol ACH; aluminum metana; aluminium aluminum chloride chloride hydroxide oxide, bronze; aluminum (1:3); Pearsall basic; aluminum chloride dehydrated; aluminium oxide; aluminum oxychloride; flake; aluminum powder; PAC 250A; Astringen; aluminum-27; Noral Chlorhydrol; Locron aluminum; PAP-1 d Chemical formula Al AlCl3 Unspecified 3+ - Chemical structure Al Al (Cl )3 Unspecified Identification numbers: CAS registry 7429-90-5 7446-70-0 1327-41-9 EINECS 231-072-3 231-208-1 215-477-2 NIOSH RTECS BD330000 BD0525000 No data EPA hazardous waste No data D003 No data code EPA Pesticide 000111 013901 No data Chemical Code DOT/UN/NA/IMCO UN 1309; UN 1396; IMO UN 1726; UN 2581; No data shipping 4.1; IMO 4.3; NA 9260 IMO 8.0 HSDB 507 607 No data ALUMINUM 147 4. -
Characteristics and Stability of Oxide Films on Plutonium Surfaces
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Student Research Projects, Dissertations, and Theses - Chemistry Department Chemistry, Department of 12-2010 Characteristics and Stability of Oxide Films on Plutonium Surfaces Harry Guillermo García Flores University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/chemistrydiss Part of the Physical Chemistry Commons García Flores, Harry Guillermo, "Characteristics and Stability of Oxide Films on Plutonium Surfaces" (2010). Student Research Projects, Dissertations, and Theses - Chemistry Department. 17. https://digitalcommons.unl.edu/chemistrydiss/17 This Article is brought to you for free and open access by the Chemistry, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Student Research Projects, Dissertations, and Theses - Chemistry Department by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. CHARACTERISTICS AND STABILITY OF OXIDE FILMS ON PLUTONIUM SURFACES by Harry G. García Flores A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy Major: Chemistry Under the Supervision of Professor Marjorie A. Langell Lincoln, Nebraska December, 2010 CHARACTERISTICS AND STABILITY OF OXIDE FILMS ON PLUTONIUM SURFACES Harry Guillermo García Flores, Ph.D. University of Nebraska, 2010 Adviser: Marjorie A. Langell The oxidation of plutonium (Pu) metal continues to be an area of considerable activity. The reaction characteristics have significant implications for production use, storage, and disposition of this radiological material. Developing an accurate physical model of the structures, oxidation states, and oxygen concentration gradients present during oxidation are essential to understanding this process. -
The Electrochemical Reduction of Chromium Sesquioxide in Molten Calcium Chloride Under Cathodic Potential Control
The Electrochemical Reduction of Chromium Sesquioxide in Molten Calcium Chloride under Cathodic Potential Control Carsten Schwandt and Derek J. Fray Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB2 3QZ, United Kingdom Reprint requests to C. S.; Fax: +44-(0)1223-334567; E-mail: [email protected] Z. Naturforsch. 62a, 655 – 670 (2007); received June 13, 2007 Presented at the EUCHEM Conference on Molten Salts and Ionic Liquids, Hammamet, Tunisia, September 16 – 22, 2006. Electrochemical polarization and reduction experiments are reported which were performed with a three-terminal cell and a molten salt electrolyte consisting of calcium chloride with additions of calcium oxide. Employing a metal cathode, a graphite anode and a pseudo-reference electrode also made from graphite, polarization measurements were carried out with the aim to validate the per- formance of the pseudo-reference electrode and to assess the stability of the electrolyte. Using a chromium sesquioxide cathode in conjunction with a graphite anode and a graphite pseudo-reference electrode, electrochemical reduction experiments were conducted under potentiostatic control. The key results are: a graphite pseudo-reference electrode has been shown to be appropriate in the present type of molten salt electrochemical experiments that take place on a time scale of many hours; the conversion of chromium oxide into chromium metal has been accomplished under cathodic potential control and in the absence of calcium metal deposition; a significant amount of calcium oxide in the calcium chloride has been found necessary to preclude anodic chlorine formation throughout the en- tire experiment; a considerable overpotential has been identified at the anode. -
Soil Survey Laboratory Information Manual, Version 2.0 (SSIR No
Soil Survey Laboratory Information Manual Soil Survey Investigations Report No. 45 Version 2.0 February 2011 Compiled and Edited by Rebecca Burt United States Department of Agriculture Natural Resources Conservation Service National Soil Survey Center Lincoln, Nebraska Cover Photos: The soil survey landscape (upper left) and pedon (upper right) are from Lyon County, Nevada. The landscape is a typical area of Cleaver soils, and the pedon is representative of the Cleaver series. Cleaver soils are classified as loamy, mixed, superactive, mesic, shallow Typic Argidurids. These well drained soils are shallow to an indurated duripan. They formed in alluvium derived from igneous rocks and are on fan remnants in the Great Basin section of the Basin and Range physiographic province. The present vegetation in the rangeland ecological site is mainly Bailey’s greasewood (Sarcobatus baileyi), shadscale (Atriplex confertifolia), winterfat (Krascheninnikovia lanata), Nevada jointfir (Ephedra nevadensis), and cheatgrass (Bromus tectorum). (Photos courtesy of Joseph V. Chiaretti, NRCS, National Soil Survey Center, Lincoln, Nebraska.) Lower left: The National Soil Survey Laboratory in Lincoln, Nebraska. Lower right: A thin section. Soil Survey Laboratory Information Manual Soil Survey Investigations Report No. 45 Version 2.0 February 2011 Compiled and Edited by Rebecca Burt United States Department of Agriculture Natural Resources Conservation Service National Soil Survey Center Lincoln, Nebraska i Trade names are used in this manual solely for the purpose of providing specific information. Mention of a trade name does not constitute a guarantee of the product by the USDA nor does it imply an endorsement by the USDA. ______________________________________________________________________ USDA Nondiscrimination Statement The U.S. -
Chemistry of Group 13 Elements
Chemistry of Group 13 Elements (Prepared by Prof. S. Bhattacharya as a study material for B.Sc. Sem II students) GENERAL FEATURES Element (symbol) Electronic Configuration Oxidation State Atomic / Metallic Radius (Å) B [He] 2s22p1 III 0.885 Al [Ne] 3s23p1 (I) III 1.43 Ga [Ar] 4s24p1 I III 1.225 In [Kr] 5s25p1 I III 1.67 Tl [Xe] 6s26p1 I III 1.70 • Oxidation state III is common, however, stability of oxidation state (I) increases down the group. (Inert pair Effect) • Anomalous reduction in size from Al to Ga is due to the presence of 10 d electrons in the penultimate shell which shield the nuclear charge less effectively • Boron is a typical non-metal obtained by reduction of B2O3 as an amorphous black solid. All other elements are metals. • Aluminum is the most abundant element in the earth’s crust. Gallium has a very low M.P. (30 oC) though its density (at room temp) more than twice of that of Al. • Oxidation state of (I) is more stable in case of Tl. Tl(I) salts are poisonous. OXIDES OF BORON AND RELATED COMPOUNDS 1. Orthoboric Acid Structure 2 B(OH)3 is trigonal planar (sp hybridization of orbitals of central boron). In solid state B(OH)3 units are hydrogen bonded together into 2D sheets with almost hexagonal symmetry. Distance between any two layers is quite large (3.18 Å) as a result crystals easily break into fine powders H H O O H H H B H O O O B H B H H H O O O O H H H H O O O O H H H B H B O O O H H H B H O O H H Chemical Nature - H3BO3 [or B(OH)3] is a weak acid. -
VANADIUM PENTOXIDE Pp197-226.Qxd 31/05/2006 09:38 Page 226 Pp227-292.Qxp 31/05/2006 09:49 Page 227
pp197-226.qxd 31/05/2006 09:38 Page 225 VANADIUM PENTOXIDE pp197-226.qxd 31/05/2006 09:38 Page 226 pp227-292.qxp 31/05/2006 09:49 Page 227 VANADIUM PENTOXIDE 1. Exposure Data 1.1 Chemical and physical data 1.1.1 Nomenclature The nomenclature of selected vanadium compounds is given in Table 1. Chem. Abstr. Serv. Reg. No.: 1314-62-1 Deleted CAS Reg. No.: 12503-98-9; 56870-07-6; 87854-55-5; 87854-56-6; 166165- 37-3; 172928-47-1; 184892-22-6; 200577-85-1; 203812-34-4; 251927-12-5; 410546- 90-6 Chem. Abstr. Serv. Name: Vanadium oxide (V2O5) IUPAC Systematic Name: Vanadium oxide Synonyms: CI 77938; divanadium pentaoxide; pentaoxodivanadium; vanadic acid anhydride; vanadin (V) oxide (see also Table 1) 1.1.2 Empirical formula and relative molecular mass V2O5 Relative molecular mass: 181.88 1.1.3 Chemical and physical properties of the pure substance (a) Description: Yellow to rust-brown orthorhombic crystals (O’Neil, 2001; Lide, 2003); yellow-orange powder or dark-gray flakes (Bauer et al., 2003; National Institute for Occupational Safety and Health, 2005) (b) Boiling-point: 1800 °C, decomposes (Lide, 2003) (c) Melting-point: 670 °C (Lide, 2003); 690 °C (O’Neil, 2001) (d ) Density: 3.36 (O’Neil, 2001; Lide, 2003) (e) Solubility: Slightly soluble in water (0.1−0.8 g/100 cm3); soluble in concentrated acids and alkalis; insoluble in ethanol (Woolery, 1997; O’Neil, 2001) ( f ) Stability: Reacts with chlorine or hydrochloric acid to form vanadium oxytri- chloride; absorbs moisture from the air (ESPI, 1994).