Determination and Use of Stability Constants


Book Description

This book describes potentiometric methods for determining stability constants and explains how these constants can be used to describe metal ion speciation in complex environmental and biological systems. It also provides three original computer programs on a disk for calculating stability constants and for using stability constants to calculate concentrations of molecular species in solution. The author gives examples of calculations for simple metal chelates, for metal complexes of large organic molecules, and for mixtures containing several metal ions and complexing agents in aqueous solution. They also describe common errors in calculating stability constants and how to avoid them. This carefully revised second edition is now even more useful to the reader, and, in particular, to those who make use of the program disk. Each program has been revised to improve speed, control, and error trapping.




CRITICAL STABILITY CONSTANTS


Book Description




Computational Methods for the Determination of Formation Constants


Book Description

This volume is concerned with methods that are available for the calculation of for mation constants, in particular computational procedures. Although graphical meth ods have considerable value in the exploration of primary (raw) data they have been overtaken by computational methods, which, for the most part, take primary data and return the refined formation constants. Graphical methods are now considered com plementary to these general computational procedures. This volume brings together programs that span the lifetime of computer-assisted determination of formation constants. On one hand the reader will find listings of programs that are derived from LETAGROP (b.l961) and the GAUSS-G/SCOGS (b. 1962) families. On the other hand programs are presented that are the newest mem bers of the SCOGS lineage and from the on-going MINIQUAD series. One program is presented that describes a computational approach to the classical Hedstrom Osterberg methods; another that takes care of electrode calibration in a simple yet rigorous manner. Potentiometry and spectrophotometry are the most popular experimental tech niques for equilibrium studies, and the programs in this volume reflect this. Four programs handle potentiometric data, two will process spectrophotometric data, and one makes use of both types of data separately or in combination.




The Determination of Ionization Constants


Book Description

This practical manual is devised for organic chemists and biochemists who, in the course of their researches and without previous experience, need to determine an ionization constant. We are gratified that earlier editions were much used for this purpose and that they also proved adequate for the in service training of technicians and technical officers to provide a Department with a pK service. The features of previous editions that gave this wide appeal have been retained, but the subject matter has been revised, extended, and brought up to date. We present two new chapters, one of which describes the determination of the stability constants of the complexes which organic ligands form with metal cations. The other describes the use of more recently introduced techniques for the determination of ionization constants, such as Raman and nuclear magnetic resonance spectroscopy, thermometric titrations, and paper electro phoresis. Chapter 1 gives enhanced help in choosing between alternative methods for determining ionization constants. The two chapters on potentiometric methods have been extensively revised in the light of newer understanding of electrode processes and of the present state of the art in instrumen tation.




A Textbook of Inorganic Chemistry – Volume 1


Book Description

An advanced-level textbook of inorganic chemistry for the graduate (B.Sc) and postgraduate (M.Sc) students of Indian and foreign universities. This book is a part of four volume series, entitled "A Textbook of Inorganic Chemistry – Volume I, II, III, IV". CONTENTS: Chapter 1. Stereochemistry and Bonding in Main Group Compounds: VSEPR theory; dπ -pπ bonds; Bent rule and energetic of hybridization. Chapter 2. Metal-Ligand Equilibria in Solution: Stepwise and overall formation constants and their interactions; Trends in stepwise constants; Factors affecting stability of metal complexes with reference to the nature of metal ion and ligand; Chelate effect and its thermodynamic origin; Determination of binary formation constants by pH-metry and spectrophotometry. Chapter 3. Reaction Mechanism of Transition Metal Complexes – I: Inert and labile complexes; Mechanisms for ligand replacement reactions; Formation of complexes from aquo ions; Ligand displacement reactions in octahedral complexes- acid hydrolysis, base hydrolysis; Racemization of tris chelate complexes; Electrophilic attack on ligands. Chapter 4. Reaction Mechanism of Transition Metal Complexes – II: Mechanism of ligand displacement reactions in square planar complexes; The trans effect; Theories of trans effect; Mechanism of electron transfer reactions – types; outer sphere electron transfer mechanism and inner sphere electron transfer mechanism; Electron exchange. Chapter 5. Isopoly and Heteropoly Acids and Salts: Isopoly and Heteropoly acids and salts of Mo and W: structures of isopoly and heteropoly anions. Chapter 6. Crystal Structures: Structures of some binary and ternary compounds such as fluorite, antifluorite, rutile, antirutile, crystobalite, layer lattices- CdI2, BiI3; ReO3, Mn2O3, corundum, pervoskite, Ilmenite and Calcite. Chapter 7. Metal-Ligand Bonding: Limitation of crystal field theory; Molecular orbital theory: octahedral, tetrahedral or square planar complexes; π-bonding and molecular orbital theory. Chapter 8. Electronic Spectra of Transition Metal Complexes: Spectroscopic ground states, Correlation and spin-orbit coupling in free ions for Ist series of transition metals; Orgel and Tanabe-Sugano diagrams for transition metal complexes (d1 – d9 states); Calculation of Dq, B and β parameters; Effect of distortion on the d-orbital energy levels; Structural evidence from electronic spectrum; John-Tellar effect; Spectrochemical and nephalauxetic series; Charge transfer spectra; Electronic spectra of molecular addition compounds. Chapter 9. Magantic Properties of Transition Metal Complexes: Elementary theory of magneto - chemistry; Guoy’s method for determination of magnetic susceptibility; Calculation of magnetic moments; Magnetic properties of free ions; Orbital contribution, effect of ligand-field; Application of magneto-chemistry in structure determination; Magnetic exchange coupling and spin state cross over. Chapter 10. Metal Clusters: Structure and bonding in higher boranes; Wade’s rules; Carboranes; Metal carbonyl clusters - low nuclearity carbonyl clusters; Total electron count (TEC). Chapter 11. Metal-π Complexes: Metal carbonyls: structure and bonding; Vibrational spectra of metal carbonyls for bonding and structure elucidation; Important reactions of metal carbonyls; Preparation, bonding, structure and important reactions of transition metal nitrosyl, dinitrogen and dioxygen complexes; Tertiary phosphine as ligand.




The Determination of Stability Constants


Book Description

This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.




Metal Complexes in Aqueous Solutions


Book Description

Stability constants are fundamental to understanding the behavior of metal ions in aqueous solution. Such understanding is important in a wide variety of areas, such as metal ions in biology, biomedical applications, metal ions in the environment, extraction metallurgy, food chemistry, and metal ions in many industrial processes. In spite of this importance, it appears that many inorganic chemists have lost an appreciation for the importance of stability constants, and the thermodynamic aspects of complex formation, with attention focused over the last thirty years on newer areas, such as organometallic chemistry. This book is an attempt to show the richness of chemistry that can be revealed by stability constants, when measured as part of an overall strategy aimed at understanding the complexing properties of a particular ligand or metal ion. Thus, for example, there are numerous crystal structures of the Li+ ion with crown ethers. What do these indicate to us about the chemistry of Li+ with crown ethers? In fact, most of these crystal structures are in a sense misleading, in that the Li+ ion forms no complexes, or at best very weak complexes, with familiar crown ethers such as l2-crown-4, in any known solvent. Thus, without the stability constants, our understanding of the chemistry of a metal ion with any particular ligand must be regarded as incomplete. In this book we attempt to show how stability constants can reveal factors in ligand design which could not readily be deduced from any other physical technique.




Principles of Polarography


Book Description

Principles of Polarography is a revised and extended version of an original Czech edition that appeared in 1962 at the Publishing House of the Czechoslovak Academy of Sciences in Prague. Based on a one-term course of lectures for third-year students of chemistry at the Charles University it brings the fundamental results of more than forty years' research in the field of polarography. The book contains 22 chapters and opens with a discussion of the principles of polarography. This is followed by separate chapters on polarizable electrodes used in polarography; charging current; influence of the resistance of the electrolyte on polarographic curves; migration and diffusion-controlled currents; and equation of a reversible polarographic wave. Subsequent chapters deal with reversible processes controlled by diffusion of complex ions; reversible reduction of organic substances; deposition of mercury ions; irreversible electrode processes; applications of limiting currents; polarographic curves for the formation of semiquinones and dimers; and catalytic hydrogen currents.




Cyclodextrin Fundamentals, Reactivity and Analysis


Book Description

This book is the first volume of two volumes on cyclodextrins published in the series Environmental Chemistry for a Sustainable World. After a brief description of the cyclodextrin fundamentals, the first chapter by Grégorio Crini et al. provides an overview of cyclodextrin research during the last 5 years. The second chapter by Michal Řezanka discusses the synthesis of novel cyclodextrin systems by selective modifications. Then Eric Monflier et al. describes the synthesis of nanostructured porous materials based on cyclodextrins, and applications in heterogeneous catalysis and photocatalysis. The use of thermal analyses for assessing cyclodextrin inclusion complexes is reviewed in chapter 4 by Daniel Hădărugă et al. Experimental methods for measuring binding constants of cyclodextrin inclusion compounds are presented by David Landy. The second volume reviews cyclodextrin applications in medicine, food, environment and liquid crystals.




Instability Constants of Complex Compounds


Book Description

In recent years many research workers have turned their attention to the quantitative characterization of complex compounds and reactions of complex-formation in solution. Instability constants characterize quantitatively the equili bria in solutions of complex compounds and are extensively used by chemists of widely-varying specialities, in analytical chemistry, electrochemistry, the technology of non-ferrous and rare metals, etc., for calculations of various kinds. Despite the wealth of numerical data, no reasonably full coliection of instability constants of complex compounds has been made until now. The various individual collections of data are far from complete and in most cases omit references to the source materials. Moreover, the present state of the chemistry of complex compounds most urgently demands the complete systematization of data on instability constants and an extension of work in this field which would take advantage of the latest physico-chemical methods. The present work contains instability constants for 1,381 complex compounds. We have considered it convenient to preface the summary of the instability constants with an introductory section of a general theoretical character. This section deals with methods for the calculation of instability constants from experimental data, the influence of external conditions, such as temperature and ionic strength, on the stability of com plexes, and the principal factors determining the stability of complex compounds in aqueous solution. (vii) PREFACE In compiling the summary we have used the original litera ture and abstracts for the most part up to 1954, and some work published in 1955-1956.