THE INORGANIC CHEMISTRY OF MATERIALS How to Make Things out of Elements

THE INORGANIC CHEMISTRY OF MATERIALS How to Make Things out of Elements

Paul J. van der Put Delft University of Technology Delft, The Netherlands

Springer Science+ Business Media, LLC

L i b r a r y of Congress Cata log1ng-1n-Publ1 c a t i o n Data

P u t , Paul J . van d e r . The Inorganic chemist ry of m a t e r i a l s : how to make th ings out of

elements / Paul J . van der P u t . p. cm.

Inc ludes b i b l i o g r a p h i c a l r e f e r e n c e s and Index.

1. C h e m i s t r y , I n o r g a n i c . 2 . Inorgan ic compounds—Synthes is . 3. M a t e r i a l s . I. T i t l e . QD151.2.P89 1998 546—dc21 98-33993

CIP

ISBN 978-1-4899-0097-5 ISBN 978-1-4899-0095-1 (eBook) DOI 10.1007/978-1-4899-0095-1

© Springer Science+Business Media New York 1998 Originally published by Plenum Press, New York in 1998 Softcover reprint of the hardcover 1st edition 1998

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PREFACE

The devil may write chemical textbooks because every few years the whole thing changes.

BERZELIUS

The basis of all technology involving materials is chemistry and physics, and technologists who deal with matter need skills in both fields. The technology of each class of material depends on physics and chemistry and the degree of need for each of them is different from one type of material to the next. It can roughly be said that metallurgy is mainly physical, a ceramicist needs more (inorganic) chemistry, and polymer science combines organic chemistry with continuum physics. Chemistry remains underrepresented in materials science curricula, although it has a consider­able impact on materials technology. This book is an attempt to fill that gap in materials education.

Inorganic chemistry of materials includes those parts of inorganic chemistry or the chemistry of elements that can be used to make products. It is not one single subject but consists of several widely different disciplines, such as structural chemis­try, coordination chemistry, and solid state ionics, to name but a few. These subjects have much chemistry in common and to show their function for materials technol­ogy a text on materials chemistry should integrate these different parts of the chemistry of the elements.

There exist excellent introductions to inorganic chemistry* and monographs on all subjects in inorganic chemistry. A selection of monographs might be used in a thorough course. However, in the initial stages of study it is not easy to grasp the significance of the different chemistries from monographs alone. Moreover those who lack time for a thorough training in inorganic chemistry have no patience for what they see as scientific luxuries in academic treatises. When technologists are hunting for facts they need them fast. They have developed the habit when reading of skipping whatever is not of immediate use, and monographs necessarily have too much of that. Moreover, introductory chapters on chemistry addressed to students

*M. Silberberg. Chemistry: The Molecular Nature of Matter and Change. Mosby, St. Louis (1996). D. F. Shriver, P. W. Atkins, and C. H. Langford. Inorganic Chemistry. Oxford University Press, Oxford (1990). L. L. Zumdahl. Chemistry. D. C. Heath, Lexington (1989).

v

The Inorganic Chemistry of Materials

Chemical Technology: production of matter materials and colISIDIftilbles

Organic technology Inorganic technology

Biotechnology Synthetic organics Nonmetala Metala

Wood joo" Plastics PIItutrtac. Single crystals jfwtlIIZfIT Steel Leather PIuumaca Fibers Pestlcldes Ceramics Resources Nonferro Fibers Soap Glasses elt_kllls Paper jMel

A rough grouping of the four types of matter in materials for durable products and matter that is consumed (in italics).

in materials engineering* are limited to structural chemistry and omit the subjects that may be of the most use in practice, such as solid state and surface chemistry.

This book on the inorganic chemistry of materials collects those parts of chemistry that are basic for practicing technologists whose job is to adapt matter for a purpose. It is directed to users who are not primarily after scientific insight for its own sake but who want hard chemical facts in order to make a material. It does not provide extensive discussions of the subjects that are covered in detail in orthodox textbooks (quantum chemistry, molecular reaction mechan­isms, equilibrium thermodynamics) but instead includes essential topics that other books on inorganic chemistry neglect or ignore (solid state kinetics, design, and morphogenesis).

Roughly speaking there are two types of matter that concern the technologist: consumables, or matter for consumption, and materials, or matter from which to make durable products (see the accompaning illustration). Consumables are mostly molecular substances and most of them are organic compounds such as food, drugs, pesticides, soap, and fuel oil products. Inorganic consumables are fertilizers and mineral resources. The other part of matter that concerns the technologists is materials or matter for durable use. Most but not all of the solid compounds in this category are inorganic. The chemistry of bulk inorganic chemicals for consumptiont is not discussed here, nor are organic materials.

Synthesis is basic for materials chemistry. Teaching synthesis raises the issues of the specific versus the general and technology versus science. Directions for synthesis are very matter-specific and relations with generalities are rarely given, because they do not seem to be very helpful from the point of view of the laboratory worker. That might call for a major revision of chemical theory some day. However, the importance of science for technology is generally overrated. One observes and the other makes. Making artifacts with the desired properties (i.e., synthesis) and their

.c. W. Callister. Materials Science and Engineering: An Introduction. Wiley, New York (1994). C. Newey and G. Weaver. Materials Principles and Practice. Butterworth and Heinemann, Milton Keynes (1991).

tWo Buechner, R. Schliebs, G. Winter, K. H. Buechel. Industrial Inorganic Chemistry. VCH, Weinheim (1989). R. Thompson (cd). Industrial Inorganic Chemicals: Production and Uses. Royal Chemical Society, Cambridge (1995).

vi

design distinguishes the professions from the sciences. Ironically, engineering schools have gradually become schools of scientific physics and mathematics. The reason for this remarkable neglect of needs is that academic respectability calls for subject matter that is intellectually tough, analytic, formalizable, and teachable, while design and technology is in large measure intellectually soft, intuitive, informal, and cook­booky.* This poses a dilemma for any textbook on technology. Creativity cannot be taught and the directions in Chapter 9 should not be expected to aim for that.

This book is addressed to four groups of users who work in different fields but share a need for inorganic synthesis, a key subject for all of them:

1. Students of materials science and technology: There is more to materials science than a physical description of crystal structure and the microstructure of solids. Materials scientists are appreciated mainly for their skill in making matter do what is wanted of it. They have to be able to put atoms in their place and that is doing chemistry. The synthetic chemistry of functional and structural materials is central to this textbook. Nonmetallic inorganic materials get much less coverage in textbooks than metals and plastics although they are increasingly discussed in the biannual conferences of the Materials Research Society. The programs of those conferences indicate where the attention is now: some 4% of the subjects are devoted to metals, 16% to plastics, 50% to inorganic nonmetallic materials, and 30% to general characterization. This shift in focus is reflected in this book.

2. Students of chemical engineering. The range of synthetic processes is not restricted to the unit operations that are usually taught to the chemical engineer (basically applied physics of fluids). Synthesis of inorganic materials also includes methods such as forging, casting, sintering, hot-pressing, crystal growth, and lith­ography for making integrated circuits in semiconductor technology. The world is not a soup of organic molecules subject only to the established rules of transport phenomena. An area that is rightly ignored by chemical engineers is the current academic model for the chemical bond. However, by doing so they miss opportuni­ties: good models of the chemical bond are reliable in their predictions and engineers involved in creating or modifying materials need them. Some of them are collected in this book.

3. Product designers in need of novel materials. Product designers often concen­trate on shaping and they usually choose their materials from a list of what is available. However, available materials exist because they have been optimized for other purposes than those aimed for in the new application, and materials designers should be aware of that. Designing a product is an activity that includes develop­ment of materials because the functions wanted are strongly related to the fabrica­tion process for materials. This book tries to show how the design of products extends to creating materials and property combinations that do not yet exist.

4. Students of chemistry. This book has not much to add to subjects that are readily available in other books on chemistry and usually the individual subjects are much better presented there. Yet this nonfundamental and pragmatic text should be useful to academic chemists at the beginning of their careers. After graduation, chemists are predominantly employed in the professions. In their job the applications of chemistry prevail rather than its fundamentals and that means that some reschooling for the real world remains necessary. This book shows which parts of

*M. Diani (ed.). The Immaterial Society. Prentice Hall, Englewood Cliffs (1992).

vii

Preface

The Inorganic Chemistry of Materials

academic chemistry are applicable in technology. There is also the need for less specialization. Graduates in inorganic chemistry know much about inorganic molecules or about solids but they might profit from being conversant with both. Much practical inorganic chemistry is also developed by materials technologists outside the chemical institutes and that work is less accessible for chemists because it is not published in the journals that are most familiar to them. Even the practicing organic chemist needs familiarity with inorganic compounds, particularly solids, as most organic chemicals are made with reactions involving inorganic catalysts.

Inorganic chemistry of materials is a vast subject and for the sake of being comprehensive the style of this text is inevitably terse. Many items are mentioned but not elaborated. For a more relaxed treatment of them the various references cited should be browsed. This textbook on the inorganic chemistry of materials is not a collection of recipes but supplies a chemical basis. It differs from other treatments on the following issues: (1) It is on synthesis rather than on characteriz­ation. (2) It collects those parts of academic chemistry that can be used for materials and parts of chemistry developed in other disciplines. (3) It includes subjects that other textbooks on materials science and technology neglect, such as the chemical bond, morphogenesis, and design.

Finally I would like to mention many others who contributed to this book. First of all, Evelyn Grossberg, for a critical reading of the final manuscript. The book grew out of discussions with graduate students in the Faculty of Chemical Engineering and Materials Science at the University of Technology in Delft, The Netherlands. Also many consultants and engineers working in industry, in development depart­ments, and in production as well as scientists and technologists at uncountable conferences taught me the essentials of our trade. I am pleased to acknowledge my debt to them all.

P. J. van der Put Delft

viii

CONTENTS

Chapter 1 Introduction

1.1. The Technology of Materials . . . . 1.2. The Periodic Table . . . . . . . . 1.3. Types of Matter: Structure and Bonding 1.4. Chemical Change . . . . . . . . 1.5. Relations to other Monodisciplines 1.6. The Use of Models Exercises . References . . . . . .

Chapter 2 The Chemical Bond

2.1. Introduction . . 2.2. Valence Electrons on Atoms and Interaction with Light

2.2.1. Electrons in Atomic Shells . . . . . . . . . . 2.2.2. Interaction with Light. . . . . . . . . . . .

2.3. Orbitals: Molecular Orbital and Valence Bond Models 2.4. The Coordinative Bond in Complexes 2.5. Bonding in Ionic Compounds . . . . . . . . . . 2.6. The Miedema Model for Intermetallics . . . . . . 2.7. The Pearson Model: Electronegativity Equalization. 2.8. Linnett's Localized Electron Model for Molecules 2.9. Johnson's Interstitial Electron Model for Metals 2.10. The Phlogiston Model Exercises References . . . . . . . .

Ix

1

1 4 9

17 20 24 28 29

31

31 34 34 39 44 51 56 58 63 68 72 76 84 85

The Inorganic Chemistry of Materials

Chapter 3 Inorganic Molecules

3.1. Introduction to Inorganic Molecules. 3.2. Complexes and Their Chemistry

3.2.1. Ligand Exchange .... 3.2.2. Redox Reactions . . . .

3.3. Molecules with Covalent Bonds . 3.4. Inorganic Polymers Exercises References . . . . . .

Chapter 4 Structural Solid State Chemistry

4.1. Crystal Chemistry .. ..... 4.2. Amorphous Solids and Icosahedral Phases

4.2.1. Glass . . . . . . . . . . . . . 4.2.2. Glass Ceramics . . . . . . . . . 4.2.3. Quasi-Crystals or Icosahedral Phases.

4.3. Boron and Borides . . . 4.3.1. Elementary Boron ........ . 4.3.2. Metal Borides. . . . . . . . . . . 4.3.3. Compounds of Boron with Nonmetallic Elements

4.4. Carbides and Nitrides . . 4.5. Oxides . . . . . . . . .

4.5.1. Structural Ceramics . 4.5.2. Functional Ceramics .

4.6. Intermetallics 4.7. Intrinsic Properties . . . .

4.7.1. Electron Conductivity 4.7.2. Dielectric Properties 4.7.3. Ion Conductivity . . 4.7.4. Magnetic Properties . 4.7.5. Mechanical Properties 4.7.6. Optical Properties . 4.7.7. Chemical Properties 4.7.8. Thermal Properties

Exercises References . . . . . . . . .

Chapter 5 Solid State Reactions

5.1. Introduction . . . . 5.2. Types of Reactions of Solids

x

87

87 90 92 98

101 105 109 110

111

111 113 116 119 120 121 121 123 126 128 131 131 136 142 145 146 149 151 151 153 154 157 157 164 165

167

167 168

5.3. Kinetics of Solid State Reactions . . . . 5.4. Measuring Solid State Reaction Kinetics . 5.5. The Chemistry of Ceramics and Sintering .

5.5.1. Physical Solid State Sintering . 5.5.2. Liquid-Phase Physical Sintering 5.5.3. Reactive Sintering

Exercises References . . . . . . . .

Chapter 6

The Chemistry of Inorganic Surfaces

6.1. Surface Chemistry . . . . . . . . . 6.2. Physical Properties of Inorganic Solid Surfaces 6.3. Inorganic Colloids . . . . . . . . . . 6.4. Heterogeneous Catalysis . . . . . . . . . . 6.5. Growth of Crystalline Solids from Liquids . . 6.6. Converting Solids by Reaction with a Gaseous Reactant 6.7. Chemical Vapor Deposition . . . . . . . . . . . .

6.7.1. Operational Aspects and Equipment ..... . 6.7.2. Physical Chemistry of Chemical Vapor Deposition 6.7.3. The Pyrolytic Regime 6.7.4. Powder Synthesis . . . . . . . . . . . 6.7.5. The Catalytic Regime . . . . . . . . . 6.7.6. Diffusion Limitation in the Dialytic Regime 6.7.7. Morphology Control. . . . . . . . . .

6.8. High-Temperature Corrosion ....... . 6.9. Surface Modification by Immobilization of Molecules Exercises References . . . . . . . . . . . . . . . . . . . . .

Chapter 7

Inorganic Morphogenesis

7.1. Introduction to the Chemistry of Microstructure and Nanostructure . . . . . .

7.2. Extrinsic Properties of Materials . . . . . . . 7.3. Fractal Dimensions . . . . . . . . . . . . . 7.4. Simulations of Reaction-Diffusion Processes Using.

Cellular Automata . . . . . . . . . . . . . . 7.5. The Chemistry of Fractal Distributions .....

7.5.1. Processes that Generate Fractal Distributions 7.5.2. Reactions on Fractal Surfaces

Exercises ~fureoc9 ........... .

xi

171 176 177 178 186 187 189 189

191

191 195 197 202 204 206 207 209 210 212 217 220 227 230 234 237 239 240

243

243 252 254

259 263 263 267 270 270

Contents

The InorganIc ChemIstry of Materials

ChapterS Synthesis of Inorganic Materials

8.1. Introduction to Inorganic Synthesis 8.2. Solid State Reactions . . . . 8.3. Synthesis from Liquids

8.3.1. Preparation from Melts 8.3.2. Liquid Salts as Solvents 8.3.3. Hydrothermal Processes 8.3.4. Sol-Gel Method .

8.4. Gas-Phase Techniques. . . . 8.4.1. Vapor Transport . . . 8.4.2. Physical Vapor Deposition 8.4.3. Chemical Vapor Deposition. 8.4.4. Plasma Synthesis

Exercises . References . . . . . . . .

Chapter 9 The Design of Inorganic Materials

9.1. Introduction to Materials Design . . 9.2. Requirements and Constraints . . . 9.3. Combination Properties of Composites

9.3.1. Sum Properties .. 9.3.2. Product Properties 9.3.3. Morphology .

9.4. Functional Materials 9.4.1. Thermistors 9.4.2. Varistors ... 9.4.3. Active Materials.

9.5. Fabrication of Composites Exercises References . . . . . . . . .

Chapter 10 Inorganic Physical Chemistry

10.1. Introduction . . . . . . . 10.2. Equilibrium Thermodynamics 10.3. Defect Chemistry . . . . .

10.3.1. Thermal Disorder: Intrinsic Defect Concentrations 10.3.2. Doping: Extrinsic Defect Concentrations 10.3.3. Nonstoichiometry: Gas Equilibria 10.3.4. Defect Reactions 10.3.5. Applications

10.4. Diffusion in Solids . . .

xii

273

273 282 284 284 286 291 293 297 297 300 302 312 315 316

319

319 322 326 327 329 330 331 333 335 336 340 342 344

345

345 346 354 356 357 358 362 362 368

10.5. A Note on Diffusion Coefficients Exercises . References .

Index ..

xIII

377 379 380

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Contents