Chemistry of Tantalum and Niobium Fluoride Compounds (eBook)

Cover 1
Contents 10
Preface 8
Chapter 1. Introduction 14
1.1. General information on the applications of tantalum and niobium 14
1.2. Tantalum and niobium raw materials 17
1.3. Refining processes 18
1.4. Material science aspects 21
Chapter 2. Synthesis of tantalum and niobium fluoride compounds 24
2.1. Aqueous solutions 25
2.2. Non-aqueous solutions 36
2.3. Interactions with TaF5 and NbF5 37
2.4. Synthesis of oxyfluoride compounds using NbO2F and TaO2F 39
2.5. Hydrofluoride synthesis of niobium and tantalum compounds 51
Chapter 3. Crystal Chemistry of Tantalum and Niobium Fluoride Compounds 72
3.1. Island-type structure compounds 73
3.2. Compounds with chain-type structures 95
3.3. Compounds with layered-type structures 105
3.4. Compounds with framework-type structures 114
3.5. Compounds with coordination-type structures 122
3.6 Crystal chemical classification 129
Chapter 4. Tantalum and Niobium Complexes in fluoride solutions 138
4.1. Niobium-containing solutions 138
4.2. Tantalum-containing solutions 143
Chapter 5. Tantalum and niobium complexes in fluoride melts 148
5.1. Preliminary notes 148
5.2. Melting diagrams 150
5.3. Physicochemical properties 161
5.4. Vibration spectroscopy of fluoride melts 181
5.5. Main conclusions 204
Chapter 6. Thermal Properties and Decomposition of Tantalum- and Niobium-Containng Fluoride Compounds 208
6.1. Impact of temperature on solid fluoride complexes 208
6.2. Melting processes 213
6.3. Thermal decomposition of oxyfluoroniobates 215
6.4. Gaseous components 218
6.5. Main conclusions 228
Chapter 7. Ferroelectric Properties of Niobium and Tantalum Fluoride Compounds 230
7.1. General notes 230
7.2. Compounds derived from lithium metatantalate 233
7.3. Spontaneous polarization and non-linear optical effect in niobium and tantalum fluoride compounds 236
7.4. Piezoelectric, pyroelectric and related properties in M5Nb3OF18 compounds 247
Chapter 8. Fluorine Chemistry in the Processing of Tantalum and Niobium 266
8.1. General notes 266
8.2. Raw material decomposition 269
8.3. Liquid-liquid extraction 280
8.4. Preparation of tantalum and niobium oxides 305
8.5. K-salt production 329
8.6. The production of tantalum and niobium metals by reduction of fluoride melts 333
Chapter 9. Main principals of the chemistry of tantalum and niobium fluoride compounds 352
Appendix 354
X - Ray powder diffraction data of some important tantalum and niobium fluoride compounds (CuKa radiation) 354
References 368
Subject Index 396
Formula Index 402