Ions in Solution: Basic Principles of Chemical Interactions

232 Pages·1999·17.266 MB·English

by  John Burgess

Ions in Solution:
Basic Principles of Chemical Interactions
Second edition
"Talking of education, people have now a-days" (said he) "got
a strange opinion that every thing should be taught by lectures.
Now, I cannot see that lectures can do so much good as reading
the books from which the lectures are taken. I know nothing
that can be best taught by lectures, except where experiments
are to be shewn. You may teach chemistry by lectures -
You might teach making of shoes by lectures!"
James Boswell: Life ofS amuel Johnson, 1766
HORWOOD SERIES IN CHEMICAL SCIENCE
CHEMISTRY IN YOUR ENVIRO!\'MENT JACK BARRET, Imperial College London.
FU1'1>AME~ALS OF INORGANIC CHEMISTRY JACK BARRET, Imperial College London.
ORGA~IC CHEMISTRY: A Comprehensive Degree Text and Source Book H BEYER, Ernst-Moritz-Arndt University.
AQUEOUS CHE::vJISTRY OF POLONIUM S. BROWN, P. BROWN & P. WILLIAMS, University of Sydney.
IONS IN SOLUTION JOHN BURGESS, Fellow in Inorganic Chemistry, University of Leicester.
REACTIO:'ll MECHANISMS OF METAL COMPLEXES ROBERT W. HAY, University of St Andrews.
CRYSTAL STRUCTURES MARK LADD, University of Surrey.
SYMMETRY A:'llD GROUP THEORY IN CHEMISTRY MARK LADD, University of Surrey.
MOOSSBAUER SPECTROSCOPY A.G. MADDOCK, University of Cambridge.
EXPERIME!\"T AL INORGANIC/PHYSICAL CHEMISTRY MOU'.i!IR A MALA TI. Mid Kent College ofHigher Education.
PRACTICAL SO:'llOCHEMISTRY T.J. MASON & D. PETERS: Coventry University & Rostock University.
GROUP THEORY FOR CHEMISTS KIERAN C. MOLLOY, Professor oflnorganic Chemistry, University of Bath.
FU!\'DAME:'llTAL CHEMICAL KINETICS MARGARET ROBSON WRIGHT, University of St Andrews.
ENZYMES TREVOR PALMER, Professor of Life Sciences, University of Nottingham Trent.
INSTRUMEJ\"T AL METHODS IN ELECTROCHE.\USTRY SOUTHNvlPTON ELECTROCHEMISTRY GROUP.*
TOPOLOGY IN CHEMISTRY DENNIS ROUVRA Y & R. BRUCE KING, University ofGeorgia, USA.
ANTIOXIDA!\'TS I:'ll SCIENCE, TECHNOLOGY, MEDICINE & NUTRITIO:'ll ProfG. SCOTT, Aston University.
CO~CISE CHEMISTRY Of THE ELE::vJENTS SC SIEKIERSKI I J. BURGESS, Warsaw Institute I LeicesterUniversity.
THE OXIDIZED ZONE P.A. WILLIAMS, University of West Sydney.
ORGA~OMET ALLIC CHEMISTRY FRANZ L. WIMMER, University of Brunei.
FLUORIJ\"E CHEMISTRY JOHN M. WINFIELD, Professor oflnorganic Chemistry, University of Glasgow
*The Southampton Electrochemistry Group: D PLETCHER & R GREEF, Southampton University. R PEAT, Atomic
Energy Authority. L M PETER, University ofBath. & J ROBINSON, University of Warwick.
IONS IN SOLUTION: 2nd Edition
Basic Principles of Chemical Interactions
John Burgess
Fellow in Inorganic Chemistry
University of Leicester
WP
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First published by Horwood Publishing Limited, 1999; reprinted 2005
Reprinted by Woodhead Publishing Limited, 2011

© J. Burgess, 1999
The author has asserted his moral rights

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A catalogue record for this book is available from the British Library

ISBN 978-1-898563-50-1

Printed by Lightning Source
Table of contents
Author's preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
List ofsymbols and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1 Introduction
1.1 Dissolution of salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
1.2 Metal ions around the Periodic Table ......................1 6
1.3 New aqua-metal ions .................................1 7
1.4 Anions and complexes in solution .........................2 1
1.5 Model for ions in solution ..............................2 5
2 Solvation numbers
2.1 NMR spectroscopy ..................................2 8
2.2 Ion movement methods ...............................3 2
2.3 Review of solvation numbers ............................3 3
3 Ion-solvent distances
3.1 X-ray diffraction by solutions ............................3 6
3.2 Radial distribution functions ............................3 6
3.3 Results of diffraction and scattering studies ...................3 8
4 Ion-solvent interactions
4.1 Ultraviolet-visible spectroscopy ..........................4 5
4.2 Infrared and Raman spectroscopy ........................ .49
4.3 Thermochemistry of ion solvation .........................5 1
5 Acid-base behaviour: hydrolysis and polymerisation
5.1 pK values for aqua-metal ions ...........................6 2
5.2 Polymerisation .....................................6 8
5.3 Anions and ligands ..................................7 1
6 Table of contents
5.4 Complexes .......................................7 2
6 Stability constants
6.1 Definitions .......................................7 4 ·
6.2 Trends ..........................................7 5
6.3 Chelates .........................................- 80
6.4 Selectivity; macrocyclic and encapsulating ligands ..............8 3
6.5 Relevance ........................................9 2
7 Redox potentials
7 .1 Introduction and thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . 93
7.2 Aqua-metal ions ....................................9 5
7.3 Complexes ...................................... 100
7.4 Redox potentials and stability constants .................... 104
8 Kinetics and thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
9 Kinetics and mechanisms: solvent exchange
9 .1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
9.2 Mechanisms ...................................... 111
9.2 Reactivities ...................................... 121
10 Kinetics and mechanisms: complex formation
10.1 Background ..................................... 124
10.2 The Eigen-Wilkins mechanism ......................... 125
10.3 Chelate formation ................................. 129
10.4 Polydentate and macrocyclic ligands ..................... 134
10.5 Crown ethers and cryptands ........................... 138
11 Kinetics and mechanisms: substitution at complex ions
11.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
11.2 Cobalt(III) complexes .............................. 147
11.3 Platinum(II) complexes .............................. 149
11.4 Pentacyanoferrates(II) .............................. 151
11.5 Other complexes .................................. 152
12 Kinetics and mechanisms: redox reactions
12.1 Introduction ..................................... 153
12.2 The inner-sphere mechanism .......................... 155
12.3 The outer-sphere mechanism .......................... 159
12.4 Intermediates, pre-equilibria, and other complications .......... 163
12.5 Metal ion oxidation of simple species ..................... 165
12.6 Oxoanion oxidants ................................. 167
Table of contents 7
12. 7 lntramolecular electron transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
13 Past, present and future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
Further reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Exercises, problems and projects .............................. 193
John Burgess, Sc.D., Cantab
John Burgess's interest in chemistry was kindled and nurtured by three knowledgeable
and enthusiastic teachers at Queen Elizabeth's School, Barnet, Hertfordshire. After his
national service in the Royal Artillery he continued chemistry as part of the Natural
Sciences Tripos at Sidney Sussex College, Cambridge, following that with Ph.D.
research into inorganic kinetics in solution with Dr. Reg Prince. Another interlude, of
employment by Fisons Fertilizers in their Process Development Unit at Levington in
Suffolk, was followed by an I.C.I. Fellowship in association with Professor Martyn
Symons at the University of Leicester. He has been at Leicester ever since, becoming
Reader in Inorganic Chemistry and currently a University Fellow. In 1991 he was
awarded his Sc.D. by Cambridge University.
At Leicester University he has lectured at all levels, on inorganic solution chemistry,
kinetics and mechanisms, analytical and industrial chemistry, oceans and the
atmosphere, bioinorganic chemistry, and spectroscopy for biological chemists. He has
also been involved in laboratory classes at all levels from first year introductory
chemistry through to final year projects and analytical geochemistry.
His research interests have centred on inorganic reaction kinetics and mechanisms,
especially on high pressure techniques to obtain volumes of activation and on the role
of the solvent. The latter interest led him to investigate solvation of inorganic
complexes, latterly those with relevance to inorganic pharmacology and the control of
metal ion levels in the body. He has been involved in a number of "more everyday"
projects, e.g. the role of perborate in washing powders and in dental hygiene, and
corrosion resistance of sheet metal for boat construction. Currently he is involved in X
ray absorption spectroscopy (EXAFS) studies of solvation, and in the chemistry of
cyanide complexes of molybdenum and tungsten, especially their structures and
solvatochromism. These research projects involve collaboration with the Universities
of Porto, Portugal, and Krakow, Poland, respectively. Other research projects have
involved collaboration with the Technische Hochschule Darmstadt, Germany;
Comenius University, Bratislava, Slovakia; University of the West Indies, Jamaica;
and the Universities of Seville, Spain; Messina and Turin, Italy; and New Hampshire,
USA.
His first book, Metal Ions in Solution (1978), and the first edition of the present text
(1988), were both published by Ellis Horwood Limited. More recently he has co
authored with the late Martin Tobe, Inorganic Reaction Mechanisms (Addison-Wesley
Longman, 1999), and, with Vladimir Arion and Nicolai Gerbeleu, Template Synthesis
of Macrocyclic Compounds (Wiley-VCH, 1999). Shortly to appear is The Colour of
Metal Compounds, co-authored with Adam Bartecki (Gordon & Breach).
Author's preface
The general area of inorganic solution chemistry is treated rather cursorily in many
undergraduate textbooks. A number of readers of the author's Metal Ions in
Solution have over the years suggested that an undergraduate level version would be
a useful teaching aid. The initial response was to plan a pair of cassettes with
accompanying workbooks, to be produced by the Educational Techniques Subject
Group of the Royal Society of Chemistry. The first of these appeared in 1984, the
second is in preparation. Meanwhile it has been decided to make this material
available in conventional textbook format. The first draft of the manuscript for this
book consisted simply of the scripts for the cassettes. Subsequent versions have
involved a little rearrangement and considerable rewriting, but the scope and level of
the text remain very similar to those of the cassettes. The solution chemistry of
simple anions and of a selection of complexes has been added to that of metal cations,
to give a more balanced coverage of inorganic species. Topics dealt with include the
extent and nature of solvation, and some spectrscopic, thermodynamic, and kinetic
characteristics of inorganic ions in solution. Much of the book is devoted to aqueous
solutions, but several sections reflect greater knowledge of certain aspects in non
aqueous media. Some basic knowledge of inorganic and physical chemistry is
assumed, such as that acquired in the first year of an Honours Chemistry course. A
Glossary of some fundamental terms has been included in order to help readers with
limited background knowledge. Lists of Further Reading direct the reader to fuller
accounts of certain areas and also provide him/her with an introit into more detailed
or advanced treatments. The material of the book should in tum provide a basis from
which specialised final-year courses can be developed, either in pure chemistry or in
one of the ever-increasing number of joint or combined degree courses.
The list of grateful thanks to some of the many people who have helped in various
ways to guide this book from inception to publication should start with Bob Gillard,
Professor at University College Cardiff. It was his invitation to survey the current
state of this area of chemistry at the RSC Autumn Meeting held at University College
Cardiff in 1980 which led to a series of lectures around the country. This in turn,
specifically the lecture at Hull, led to the suggestion of the preparation of a cassette