Contents
1 Overview 1
1.1 Energetic materials 1
1.2 Intrinsic structures of energetic materials 6
1.3 Benefits of the introduction of intrinsic structures 11
1.4 Intention and organization of this book 14
References 14
2 Category of energetic crystals 17
2.1 Introduction 17
2.2 Criterion for categorizing energetic crystals 18
2.2.1 Primary constituent part 18
2.2.2 Type of energetic crystals 22
2.3 Category of energetic crystals 23
2.3.1 Energetic molecular crystal 23
2.3.2 Energetic ionic crystal 30
2.3.3 Energetic atomic crystal 33
2.3.4 Energetic metallic crystal 34
2.3.5 Energetic mixed-type crystal 35
2.4 Understanding of energetic crystals 37
2.4.1 Relationship between interactions of PCPs and crystal stability 37
2.4.2 Relationship between crystal types and energy content 40
2.5 Conclusions and outlooks 40
References 41
3 Application of molecular simulation methods in treating intrinsic structures of energetic materials 47
3.1 Introduction 47
3.1.1 Weight of molecular simulation in energetic material researches 48
3.1.2 Application of molecular simulation 50
3.2 Quantum chemical methods for treating energetic molecules 52
3.2.1 Overview on quantum chemical methods 53
3.2.2 Description for geometric structure 56
3.2.3 Description for electronic structure 57
3.2.4 Description for energetics 59
3.2.5 Description for reactivity 61
3.3 Dispersion-corrected DFT methods and their application 62
3.3.1 Density prediction 65
3.3.2 Geometric prediction 68
3.3.3 Lattice energy prediction 69
3.3.4 Comparison for computation efficiency 71
3.4 Molecular FF methods and their application 73
3.4.1 Classic FFs and their application 74
3.4.2 Consistent FFs and their application 78
3.4.3 Reactive force field and their application 79
3.5 Hirshfeld surface analysis method and its application 81
3.5.1 Principle 81
3.5.2 Description for intermolecular interaction 85
3.5.3 Description for a same molecule in various crystal environments 90
3.5.4 Description for a same ion in various crystal environments 92
3.5.5 Predictions for the shear sliding characteristic and impact
sensitivity 93
3.5.6 Summary of advantages and disadvantages of the Hirshfeld surface method 96
3.6 Codes and database applied for energetic molecules and crystals 96
3.6.1 Gaussian 96
3.6.2 Multiwfn 97
3.6.3 VASP 98
3.6.4 Materials Studio 99
3.6.5 DFTB 102
3.6.6 CP2K 103
3.6.7 LAMMPS 104
3.6.8 COSMOlogic 105
3.6.9 CrystalExplorer 105
3.6.10 CSD 106
3.7 Conclusions and outlooks 107
References 107
4 Energetic molecules and energetic single-component molecular crystals 127
4.1 Introduction 127
4.2 Traditional energetic molecular crystals 128
4.2.1 Energetic nitro compounds 128
4.2.2 Energetic conjugated N-heterocyclic compounds 134
4.2.3 Energetic organic azides 144
4.2.4 Energetic compounds with different heat resistance 145
4.2.5 Energetic compounds with different impact sensitivity 148
4.3 Energetic halogen compounds 150
4.3.1 Energetic fluorine compounds 150
4.3.2 Energetic compounds with chlorine�� bromine�� or iodine 153
4.4 Entropy explosives: energetic peroxides 154
4.5 Full nitrogen molecules 156
4.6 Conclusions and outlooks 163
References 163
5 Polymorphism and polymorphic transition in energetic molecular crystals 175
5.1 Introduction 175
5.2 Polymorphism and polymorphic transition 176
5.2.1 Polymorphism 176
5.2.2 Polymorphic transition 176
5.3 Factors influencing the polymorphic transition 180
5.3.1 Crystal quality 180
5.3.2 Additive 181
5.4 Polymorph-reduced differences in structure and energetics 183
5.4.1 Molecular structure 183
5.4.2 Molecular packing 186
5.4.3 Morphology 191
5.4.4 Energetics 192
5.4.5 Detonation property 196
5.5 Polymorph-dependent mechanism of thermal decomposition 197
5.5.1 CL-20 197
5.5.2 HMX 201
5.6 Polymorph transition-induced low impact sensitivity of FOX-7 206
5.6.1 Stacking structures of the FOX-7 polymorphs 207
5.6.2 Sliding characteristics of the polymorphs of FOX-7 208
5.6.3 Correlation between the low impact sensitivity of FOX-7 and its heat-induced polymorphic transition 214
5.7 Strategies for controlling polymorphic transition 215
5.7.1 Recrystallization 215
5.7.2 Coating crystal 215
5.7.3 Adding additive 216
5.8 Conclusions and outlooks 216
References 217
6 Energetic ionic crystals 227
6.1 Introduction 227
6.2 Composition and category 227
6.2.1 Composition of energetic ionic crystals 227
6.2.2 Category of energetic ionic crystals 229
6.3 Volumetric and electric variabilities of constituent ions 230
6.3.1 Volumetric variability 230
6.3.2 Electric variability 232
6.4 Packing structure and intermolecular HB 234
6.4.1 Packing structure 234
6.4.2 Intermolecular HB 236
6.4.3 Cons