The Defect Chemistry of Metal Oxides

by Smyth, D. M.

• ISBN13: 9780195110142
• ISBN10: 0195110145
• Edition: 1st
• Format: Hardcover
• Copyright: 2000-06-15
• Publisher: Oxford University Press

Summary

The Defect Chemistry of Metal Oxides is a unique introduction to the equilibrium chemistry of solid inorganic compounds with a focus on metal oxides. Accessible to students with little or no background in defect chemistry, it explains how to apply basic principles and interpret the related behavior of materials. Topics discussed include lattice and electronic defects, doping effects, nonstoichiometry, and mass and charge transport. The text distinctly emphasizes the correlation between the general chemical properties of the constituent elements and the defect chemistry and transport properties of their compounds. It covers the types of defects formed, the effects of dopants, the amount and direction of nonstoichiometry, the depths of acceptor and donor levels, and more. Concluding chapters present up-to-date and detailed analyses of three systems: titanium dioxide, cobalt oxide and nickel oxide, and barium titanate. The Defect Chemistry of Metal Oxides is the only book of its kind that incorporates sample problems for students to solve. Suitable for a variety of courses in materials science and engineering, chemistry, and geochemistry, it also serves as a valuable reference for researchers and instructors.

Table of Contents

Preface	ix
Introduction	1	(3)
Reference	3	(1)
A Few Useful Crystal Structures	4	(17)
Introduction	4	(2)
Close-Packed Structures	6	(7)
Structures for Eight-Coordinate Cations	13	(3)
Structures for Ternary Compounds	16	(4)
Conclusion	20	(1)
References	20	(1)
Problems	20	(1)
Lattice Defects and the Law of Mass Action	21	(13)
Introduction	21	(1)
Lattice Defects as Part of the Equilibrium State	22	(4)
The Law of Mass Action	26	(2)
Another View of Mass Action	28	(2)
Lattice Disorder in Elemental Solids	30	(2)
Summary	32	(1)
References	33	(1)
Intrinsic Ionic Disorder	34	(23)
Lattice Defects and Reference States	34	(2)
Conservation Rules	36	(1)
Defect Notation	37	(1)
Major Types of Intrinsic Ionic Disorder	38	(10)
General Comments on Intrinsic Ionic Disorder	48	(7)
References	55	(1)
Problems	55	(2)
Extrinsic Ionic Disorder	57	(18)
Introduction	57	(1)
The AgCl--CdCl2 System	58	(4)
The CaF2--CaO System	62	(1)
The TiO2--Nb2O5 System	63	(1)
Summary of Important Points	64	(1)
Schematic Representation of Defect Concentrations	65	(7)
Summary of Extrinsic Ionic Disorder	72	(1)
References	73	(1)
Problems	73	(2)
Defect Complexes and Associates	75	(16)
Introduction	75	(1)
Complexes Containing an Impurity Center and an Ionic Defect	76	(6)
Intrinsic Ionic Defect Associates	82	(3)
The Effect of Impurities on the Concentrations of Defect Complexes and Associates	85	(4)
References	89	(2)
Ionic Transport	91	(27)
Introduction	91	(1)
Basic Concepts of Diffusion	91	(4)
Ionic Conduction in Crystalline Solids	95	(5)
Intrinsic and Extrinsic Ionic Conduction	100	(12)
Fast Ion Conductors	112	(5)
References	117	(1)
Intrinsic Electronic Disorder	118	(20)
Introduction	118	(1)
The Development of Energy Bands	118	(3)
The Mass-Action Approach	121	(2)
The Fermi Function	123	(3)
Holes, Waves, and Effective Masses	126	(3)
Electronic Conductivity	129	(3)
Hopping Mechanisms	132	(1)
The Band Structure of Compounds	133	(1)
Chemistry and the Band Gap	134	(3)
Summary	137	(1)
References	137	(1)
Extrinsic Electronic Disorder	138	(24)
Introduction	138	(1)
Interactions with the Gaseous Ambient	138	(3)
The Choice of Compensating Defect	141	(4)
The Chemical Consequences of Electronic Compensation	145	(1)
The Interactions of Impurity Centers with Electrons and Holes	146	(10)
The Situation for Compounds	156	(5)
Summary	161	(1)
References	161	(1)
Intrinsic Nonstoichiometry	162	(35)
Introduction	162	(1)
Nonstoichiometry in Pure Crystalline Compounds	163	(4)
Nonstoichiometry and Equilibrium Defect Concentrations	167	(1)
The Hypothetical Compound MX with Schottky Disorder	167	(7)
Summary of the Kroger--Vink Diagram for MX	174	(10)
Conclusion of the Discussion of MX	184	(1)
A More Complex Kroger--Vink Diagram	185	(8)
Summary of the Kroger--Vink Diagrams for Intrinsic Nonstoichiometry	193	(1)
Enthalpy Relationships	193	(1)
Conclusion	194	(1)
Reference	194	(1)
Problems	194	(3)
Extrinsic Nonstoichimetry	197	(20)
Introduction	197	(1)
A Simple Example: Donor-Doped MX	198	(7)
Enthalpy Relationships	205	(2)
A More Complex Example: Acceptor-Doped M2O3	207	(3)
General Considerations	210	(4)
Nonstoichiometric Reactions in the Impurity-Controlled Region	214	(1)
Problems	215	(2)
Titanium Dioxide	217	(22)
Introduction	217	(3)
The Amount of Nonstoichiometry	220	(2)
The Equilibrium Electrical Conductivity of Undoped TiO2	222	(6)
The Seebeck Coefficient of Undoped TiO2	228	(1)
Ionic Conduction in TiO2	228	(2)
The Effect of Dopants on TiO2	230	(5)
General Comments on the Defect Chemistry of TiO2	235	(2)
References	237	(1)
Problems	238	(1)
Cobalt Oxide and Nickel Oxide	239	(14)
Introduction	239	(1)
Cobaltous Oxide, CoO	240	(7)
Nickelous Oxide, NiO	247	(5)
Summary	252	(1)
References	252	(1)
Barium Titanate	253	(30)
Introduction	253	(2)
General Expectations	255	(1)
The Equilibrium Conductivity of Undoped BaTiO3	256	(6)
Insulting Properties of BaTiO3	262	(6)
Acceptor-Doped BaTiO3	268	(3)
Ionic Conduction in BaTiO3	271	(4)
Donor-Doped BaTiO3	275	(3)
Trivalent Dopants in BaTiO3	278	(3)
Summary	281	(1)
References	281	(2)
Order Versus Disorder	283	(8)
Block Structures	287	(1)
Summary	288	(1)
References	289	(2)
Index	291