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Facts on File DICTIONARY of INORGANIC CHEMISTRY

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Facts on File DICTIONARY of INORGANIC CHEMISTRY The Facts On File DICTIONARY of INORGANIC CHEMISTRY The Facts On File DICTIONARY of INORGANIC CHEMISTRY Edited by John Daintith ® The Facts On File Dictionary of Inorganic Chemistry Copyright © 2004 by Market House Books Ltd All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Facts On File, Inc. 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data The Facts on File dictionary of inorganic chemistry / edited by John Daintith. p. cm. Includes bibliographical references. ISBN 0-8160-4926-2 (alk. paper). 1. Chemistry—Dictionaries. I. Title: Dictionary of inorganic chemistry. II. Daintith, John. XXXXXXXXX XXXXXXXXX XXXXXXXXXX Facts On File books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Facts On File on the World Wide Web at http://www.factsonfile.com Compiled and typeset by Market House Books Ltd, Aylesbury, UK Printed in the United States of America MP 10987654321 This book is printed on acid-free paper CONTENTS Preface vii Entries A to Z 1 Appendixes I. The Periodic Table 244 II. The Chemical Elements 245 III. The Greek Alphabet 247 IV. Fundamental Constants 247 V. Webpages 248 Bibliography 248 PREFACE This dictionary is one of a series covering the terminology and concepts used in important branches of science. The Facts on File Dictionary of Inorganic Chemistry has been designed as an additional source of information for stu- dents taking Advanced Placement (AP) Science courses in high schools. It will also be helpful to older students taking introductory college courses. This volume covers inorganic chemistry and includes basic concepts in phys- ical chemistry, classes of compound, reaction mechanisms, and many im- portant named inorganic compounds. The entries on individual chemical elements are designed to give a basic survey of the chemistry of the element. The definitions are intended to be clear and informative and, where possi- ble, we have illustrations of chemical structures. The book also has a selec- tion of short biographical entries for people who have made important contributions to the field. There are appendixes providing a list of all the chemical elements and a periodic table. A short list of useful webpages and a bibliography are also included. The book will be a helpful additional source of information for anyone studying the AP Chemistry course, especially the section on Descriptive Chemistry. It will also be useful to students of metallurgy and other related fields. ACKNOWLEDGMENTS Contributors John O. E. Clark B.Sc. Richard Rennie B.Sc., Ph.D. Tom Shields B.Sc. vii A AAS See atomic absorption spec- sorb gases or liquids often have a porous troscopy. structure. The absorption of gases in solids is sometimes called sorption. Compare ad- absolute temperature Symbol: T A sorption. temperature defined by the relationship: T = θ + 273.15 absorption indicator (adsorption indica- where θ is the Celsius temperature. The ab- tor) An indicator used for titrations that solute scale of temperature was a funda- involve a precipitation reaction. The mental scale based on Charles’ law applied method depends upon the fact that at the to an ideal gas: equivalence point there is a change in the αθ V = V0(1 + ) nature of the ions absorbed by the precipi- θ where V is the volume at temperature , V0 tate particles. Fluorescein – a fluorescent the volume at 0, and α the thermal expan- compound – is commonly used. For exam- sivity of the gas. At low pressures, when ple, in the titration of sodium chloride so- real gases show ideal behavior, α has the lution with added silver nitrate, silver value 1/273.15. Therefore, at θ = –273.15 chloride is precipitated. Sodium ions and the volume of the gas theoretically be- chloride ions are absorbed in the precipi- comes zero. In practice, of course, sub- tate. At the end point, silver ions and ni- stances become solids at these trate ions are in slight excess and silver ions temperatures. Nevertheless, the extrapola- are then absorbed. If fluorescein is present, tion can be used to create a scale of tem- negative fluorescein ions absorb in prefer- perature on which –273.15 degrees Celsius ence to nitrate ions, producing a pink com- (°C) corresponds to zero (0°). This scale plex. was also known as the ideal-gas scale; on it temperature interval units were called de- absorption spectrum See spectrum. grees absolute (°A) or degrees Kelvin (°K), and were equal in size to the Celsius de- abundance 1. The relative amount of a gree. It can be shown that the absolute tem- given element among others; for example, perature scale is identical to the the abundance of oxygen in the Earth’s THERMODYNAMIC TEMPERATURE scale, on crust is approximately 50% by mass. which the temperature interval unit is the 2. The amount of a nuclide (stable or kelvin. radioactive) relative to other nuclides of the same element in a given sample. The absolute zero The zero value of ther- natural abundance is the abundance of a modynamic temperature; 0 kelvin or nuclide as it occurs in nature. For instance, –273.15 degrees Celsius. chlorine has two stable isotopes of masses 35 and 37. The abundance of 35Cl is absorption A process in which a gas is 75.5% and that of 37Cl is 24.5%. For some taken up by a liquid or solid, or in which a elements the abundance of a particular nu- liquid is taken up by a solid. In absorption, clide depends on the source. the substance absorbed goes into the bulk of the absorping material. Solids that ab- acac Abbreviation for the bidentate 1 accelerator H 2 achiral Describing a molecule that does CH3 C CH 3 not exhibit optical activity. See chirality. C C acid A substance than contains hydro- O O gen and dissociates in solution to give hy- drogen ions: HA ˆ H+ + A– More accurately, the hydrogen ion is sol- H vated (a hydroxonium ion): ˆ + – CH3 C CH3 HA + H2O H3O + A C C Strong acids are completely dissociated in water. Examples are sulfuric acid and tri- _ choloroethanoic acid. Weak acids are only O O partially dissociated. Most organic car- Acac: the bidentate acetylacetonato ligand boxylic acids are weak acids. In distinction formed from a diketone to an acid, a base is a compound that pro- duces hydroxide ions in water. Bases are ei- acetyacetonato ligand, derived from acetyl- ther ionic hydroxides (e.g. NaOH) or acetone (CH3COCH2COCH3). compounds that form hydroxide ions in water. These may be metal oxides, for ex- accelerator A CATALYST added to in- ample: crease the rate at which a chemical reaction → + – Na2O + H2O 2Na + 2OH occurs. Ammonia, amines, and other nitrogenous compounds can also form OH– ions in acceptor The atom or group to which a water: pair of electrons is donated in a coordinate ˆ + – NH3 + H2O NH4 + OH bond. Pi-acceptors are compounds or As with acids, strong bases are completely groups that accept electrons into pi, p or d dissociated; weak bases are partially disso- orbitals. ciated. This idea of acids and bases is known as accumulator (secondary cell; storage bat- the Arrhenius theory (named for the tery) An electric cell or battery that can Swedish physical chemist Svante August be charged by passing an electric current Arrhenius (1859–1927). through it. Because the chemical reaction In 1923 the Arrhenius idea of acids and in the cell is reversible, current passed bases was extended by the British chemist through it in the opposite direction to Thomas Martin Lowry (1874–1936) and, which it supplies current will convert the independently, by the Danish physical reaction products back into their original chemist Johannes Nicolaus Brønsted forms. The most common example is the (1879–1947). In the Lowry–Brønsted lead-acid battery used in automobiles and theory an acid is a compound that can do- other vehicles powered by internal com- nate a proton and a base is a compound bustion engines. that can accept a proton. Proton donators are called Brønsted acids (or protic acids) acetate See ethanoate. and proton acceptors are called Brønsted bases. For example, in the reaction: ˆ – acetic acid See ethanoic acid. CH3COOH + H2O CH3COO + + H3O acetyacetonato See acac. the CH3COOH is the acid, donating a pro- ton H+ to the water molecule. The water is acetylene See ethyne. the base because it accepts the proton. In + the reverse reaction, the H3O ion is the Acheson process See carbon. acid, donating a proton to the base 2 actinic radiation – CH3COO . If two species are related by acidic hydrogen A hydrogen atom in a loss or gain or a proton they are described molecule that enters into a dissociation as conjugate. So, in this example, equilibrium when the molecule is dissolved – CH3COO is the conjugate base of the acid in a solvent. For example, in ethanoic acid CH3COOH and CH3COOH is the conju- (CH3COOH) the acidic hydrogen is the – gate acid of the base CH3COO . one on the carboxyl group, –COOH. In a reaction of an amine in water, for example: acidic oxide An oxide of a nonmetal ˆ + – R3N + H2O R3NH + OH that reacts with water to produce an acid The amine R3N accepts a proton from or with a base to produce a salt and water. water and is therefore acting as a base.
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