Cover images 0M urray Robertsonlvisual elements 1998-99, taken from the 109 Visual Elements Periodic Table Copyright 0T he Royal Society of Chemistry 2002. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4744. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 605 Third Avenue. New York, NY 10158-0012, (212) 850-601 I, fax (212) 850-6008, E-Mail: PERMREQ @ WILEYCOM. For ordering and customer service, call 1- 800-CALL-WILEY. Library of Congress Cataluging-in-PublicationD ata: Library of Congress Cataloging-in-Publication Data is available. ISBN: 0-47 1-22476-6 Typeset in Great Britain by Wyvern 2 1, Bristol Printed and bound by Polestar Wheatons Ltd, Exeter 10987654321 Preface At first sight it may seem strange that metallic elements such as iron or copper, which we encounter in machinery or electrical wiring, might also be intimately involved in the function of living organisms. However, our very survival depends upon the particular chemical properties of these metallic elements, which belong to the d-block series known as the ‘transi- tion metals’. To illustrate this point we might note that, after every breath we take, the oxygen we inhale is collected by the red protein haemoglobin present in our blood. The red color of blood arises from the presence of iron in this protein, and it is to this iron that the oxygen becomes attached. Through its attachment to hemoglobin, oxygen is transported in the blood to sites in the body where another protein containing both iron and copper effects its reduction. This releases energy as part of the process of respiration. What is so special about iron and copper that biology has selected them for these particular rbles? Why not nickel rather than iron? What do we need to know about their chemistry to understand why they are so specially suited to their particular functions? Apart from their rather immediate importance in maintaining life, transition elements are of major importance in enhancing the quality of our daily lives. Among the materials we encounter each day, many either contain transition elements or have been formed in processes which involve them. Even plastic materials may have required the use of a tran- sition metal catalyst in their manufxture. In order to understand the biological rdes of transition metals, or develop new chemical processes involving them, it is first necessary to understand the principles which underly the chemistry of these elements. In a short text such as this it is not possible to describe the chemistry of the transition elements in any comprehensive way, and no attempt is made to do so. Rather, it is the aim of this book to introduce some basic principles which would allow a student of the subject to make more sense iv Preface of the varied, and sometimes surprising, chemistry they may encounter when reading more comprehensive accounts of transition element chem- istry. Several short primers already exist which provide an introduction to the d- and f-block elements and it is not the aim of this text to duplicate these, but rather to complement them. The text is intended to take the reader through some of the topics cov- ered in the first two years of an undergraduate course in chemistry. It assumes some basic knowledge of topics which should be covered in oth- er courses at this level. These include atomic structure, simple quantum theory, simple thermodynamic relationships and electrode potentials. A knowledge of group theory is not explicitly required to follow the text, but reference is made to the symbols of group theory. The data in the text are based on published sources. However, it should not be assumed that data in the problems are based on actual measurements. Although report- ed data have been used where possible, some values have been calculated or invented for the purpose of the question. As with all works of this type, the final text does not reflect the input of the author alone. My thanks go to Matt Barton, Andy Millar and Steve Vickers for checking a draft of the text, and to Martyn Berry for his help- ful and insightful comments after reviewing the manuscript. However, the responsibility for any errors which remain is mine alone, although I assume no responsibility for the cover design which was beyond my control! Finally, my thanks must also go to my long-suffering wife, Judy, for her forbearance and patience whilst my attentions have been redirected to yet another ‘project’. Chris J. Jones Birmingham till IOK-I\-CIlltl E X E C UT I V E EDI TO R S E D IJC AT I 0 N A L C 0 N S IJ LT A N T Proffcssor E W Ahel Professor A G Davies Mr M Berry Professor D Phillips Projessor J D Woo1lin.c This series of books consists of short, single-topic or modular texts, concentrating on the funda- mental areas of chemistry taught in undergraduate science courses. Each book provides a concise account of the basic principles underlying a given subject, embodying an independent- learning philosophy and including worked examples. The one topic, one book approach ensures that the series is adaptable to chemistry courses across a variety of institutions. TITL1:S IN THE SEKIES Stereochemistry D G Morris Reactions and Characterization of Solids S E Dunn Main Group Chemistry W Iftvderson d- and f-Block Chemistry C J Jones Structure and Bonding J Burrett Functional Group Chemistry J R Hunson Contents 1.1 What are the Transition Elements? 1 1.2 Where do Transition Elements Come From? 4 1.3 The Historical Development of Transition Element Chemistry 7 1.4 Some Applications of the Transition Elements 14 2.1 Introduction 19 2.2 Transition Elements: Atomic Structure and Properties 20 3.1 Introduction 39 3.2 Binary Oxides, Fluorides and Chlorides 40 3.3 Thermodynamic Aspects of Compound Formation 44 4.1 Introduction 54 4.2 Coordination Compounds 55 4.3 Nomenclature 66 5.1 Introduction 72 5.2 The Thermodynamics of Complex Formation 73 5.3 Self-assembly and Metal Templated Reactions 90 vii viii Contents 6.1 Introduction 97 6.2 The Crystal Field Model 98 6.3 The Molecular Orbital Model of Bonding 113 7.1 Introduction 130 7.2 The Electronic Spectra of Metal Complexes 131 7.3 The Magnetism of Transition Element Complexes 146