1 Introduction to hybrid organic-inorganic perovskites 1
1.1 Perovskite oxides 1
1.2 Evolution from perovskite oxides to HOIPs 3
1.3 Classification and chemical variations of HOIPs 5
1.4 Structure, symmetry and property features of HOIPs 6
1.4.1 General trend 6
1.4.2 Ion radius mismatch and tolerance factor 9
1.4.3 Phase transitions 10

2 Hybrid halide perovskites 15
2.1 Synthesis and chemical diversity 15
2.2 Symmetry and structures 19
2.3 Phase transitions 26
2.4 Physical properties 31
2.4.1 Semiconductivity and bandgap structures 31
2.4.2 Transport properties and photovoltaics 37
2.4.3 Laser physics 54
2.4.4 Light-emitting diodes 60
2.4.5 Photodetectors 65
2.4.6 Ferroelectricity and Rashba effect 69
2.4.7 Mechanical properties 73
2.4.8 Thermal conductivity 78
2.4.9 Caloric effects 80
2.4.10 Other properties 82

3 Hybrid formate perovskites 92
3.1 Synthesis and chemical diversity 92
3.2 Symmetries and structures 95
3.3 Phase transitions and order-disorder 103
3.4 Physical properties 107
3.4.1 Magnetism 107
3.4.1.1 Spin-canting and JT effect 107
3.4.1.2 Spin-flop 113
3.4.1.3 Quantum tunneling 116
3.4.2 Dielectricity 117
3.4.3 Ferroelectricity 121
3.4.4 Ferroelasticity 132
3.4.5 Multiferroicity 138
3.4.6 Mechanical properties 147
3.4.7 Thermal expansion 159
3.4.8 Caloric effects 165

4
Hybrid azide perovskites 179
4.1 Synthesis and structures 179
4.2 Phase transitions 184
4.3 Physical properties 194
4.3.1 Magnetism 194
4.3.2 Dielectricity 197
4.3.3 Antiferroelectricity and ferroelasticity 204
4.3.4 Thermal expansion 2074.3.5 Mechanical properties 208

5 Hybrid dicyanomide perovskites 213
5.1 Synthesis and structures 213
5.2 Phase transitions 217
5.3 Physical properties 221
5.3.1 Dielectricity 221
5.3.2 Optical properties and second-harmonic generation effects 224
5.3.3 Magnetism 225
5.3.4 Mechanical properties and thermal expansion 227
5.3.5 Caloric effects 230

6 Hybrid cyanide perovskites 234
6.1 Synthesis and structures 234
6.2 Phase transitions 239
6.3 Physical properties 248
6.3.1 Second-harmonic generation 248
6.3.2 Dielectricity 248
6.3.3 Ferroelectricity 253

7 Hybrid dicyanometallate and borohydride perovskites 258
7.1 Hybrid dicyanometallate perovskites 258
7.1.1 Synthesis, structures and phase transitions 258
7.1.2 Physical properties 261
7.2 Hybrid boronhydride perovskites 263

8 Hybrid hypophosphite perovskites 264
8.1 Synthesis 264
8.2 Symmetries and structures 266
8.3 Phase transitions 268
8.4 Physical properties 270
8.4.1 Mechanical properties 270
8.4.2 Magnetism 271

9 Other perovskite-like hybrid materials and metal-free perovskites 274
9.1 Hybrid organic-inorganic perchlorates 274
9.1.1 Synthesis, structures and phase transitions 274
9.1.2 Physical properties 279
9.1.2.1 Mechanical properties 279
9.1.2.2 Dielectric properties 282
9.1.2.3 High energetic properties 284
9.2 Hybrid organic-inorganic tetrafluoroborates 286
9.2.1 Synthesis, structures and phase transitions 286
9.2.2 Physical properties 289
9.3 Metal-free perovskites 290
9.3.1 Synthesis, structures and electronic properties 290
9.3.2 Phase transitions 296
9.3.3 Physical properties 297
9.3.3.1 Photoluminescence 297
9.3.3.2 Ferroelectricity and dielectricity 398
9.3.3.3 Mechanical properties 302

10 Concluding remarks and future perspectives 310

1 Introduction to hybrid organic-inorganic perovskites 1
1.1 Perovskite oxides 1
1.2 Evolution from perovskite oxides to HOIPs 3
1.3 Classification and chemical variations of HOIPs 5
1.4 Structure, symmetry and property features of HOIPs 6
1.4.1 General trend 6
1.4.2 Ion radius mismatch and tolerance factor 9
1.4.3 Phase transitions 10

2 Hybrid halide perovskites 15
2.1 Synthesis and chemical diversity 15
2.2 Symmetry and structures 19
2.3 Phase transitions 26
2.4 Physical properties 31
2.4.1 Semiconductivity and bandgap structures 31
2.4.2 Transport properties and photovoltaics 37
2.4.3 Laser physics 54
2.4.4 Light-emitting diodes 60
2.4.5 Photodetectors 65
2.4.6 Ferroelectricity and Rashba effect 69
2.4.7 Mechanical properties 73
2.4.8 Thermal conductivity 78
2.4.9 Caloric effects 80
2.4.10 Other properties 82

3 Hybrid formate perovskites 92
3.1 Synthesis and chemical diversity 92
3.2 Symmetries and structures 95
3.3 Phase transitions and order-disorder 103
3.4 Physical properties 107
3.4.1 Magnetism 107
3.4.1.1 Spin-canting and JT effect 107
3.4.1.2 Spin-flop 113
3.4.1.3 Quantum tunneling 116
3.4.2 Dielectricity 117
3.4.3 Ferroelectricity 121
3.4.4 Ferroelasticity 132
3.4.5 Multiferroicity 138
3.4.6 Mechanical properties 147
3.4.7 Thermal expansion 159
3.4.8 Caloric effects 165

4
Hybrid azide perovskites 179
4.1 Synthesis and structures 179
4.2 Phase transitions 184
4.3 Physical properties 194
4.3.1 Magnetism 194
4.3.2 Dielectricity 197
4.3.3 Antiferroelectricity and ferroelasticity 204
4.3.4 Thermal expansion 2074.3.5 Mechanical properties 208

5 Hybrid dicyanomide perovskites 213
5.1 Synthesis and structures 213
5.2 Phase transitions 217
5.3 Physical properties 221
5.3.1 Dielectricity 221
5.3.2 Optical properties and second-harmonic generation effects 224
5.3.3 Magnetism 225
5.3.4 Mechanical properties and thermal expansion 227
5.3.5 Caloric effects 230

6 Hybrid cyanide perovskites 234
6.1 Synthesis and structures 234
6.2 Phase transitions 239
6.3 Physical properties 248
6.3.1 Second-harmonic generation 248
6.3.2 Dielectricity 248
6.3.3 Ferroelectricity 253

7 Hybrid dicyanometallate and borohydride perovskites 258
7.1 Hybrid dicyanometallate perovskites 258
7.1.1 Synthesis, structures and phase transitions 258
7.1.2 Physical properties 261
7.2 Hybrid boronhydride perovskites 263

8 Hybrid hypophosphite perovskites 264
8.1 Synthesis 264
8.2 Symmetries and structures 266
8.3 Phase transitions 268
8.4 Physical properties 270
8.4.1 Mechanical properties 270
8.4.2 Magnetism 271

9 Other perovskite-like hybrid materials and metal-free perovskites 274
9.1 Hybrid organic-inorganic perchlorates 274
9.1.1 Synthesis, structures and phase transitions 274
9.1.2 Physical properties 279
9.1.2.1 Mechanical properties 279
9.1.2.2 Dielectric properties 282
9.1.2.3 High energetic properties 284
9.2 Hybrid organic-inorganic tetrafluoroborates 286
9.2.1 Synthesis, structures and phase transitions 286
9.2.2 Physical properties 289
9.3 Metal-free perovskites 290
9.3.1 Synthesis, structures and electronic properties 290
9.3.2 Phase transitions 296
9.3.3 Physical properties 297
9.3.3.1 Photoluminescence 297
9.3.3.2 Ferroelectricity and dielectricity 398
9.3.3.3 Mechanical properties 302

10 Concluding remarks and future perspectives 310

1 Introduction to hybrid organic-inorganic perovskites 1
1.1 Perovskite oxides 1
1.2 Evolution from perovskite oxides to HOIPs 3
1.3 Classification and chemical variations of HOIPs 5
1.4 Structure, symmetry and property features of HOIPs 6
1.4.1 General trend 6
1.4.2 Ion radius mismatch and tolerance factor 9
1.4.3 Phase transitions 10

2 Hybrid halide perovskites 15
2.1 Synthesis and chemical diversity 15
2.2 Symmetry and structures 19
2.3 Phase transitions 26
2.4 Physical properties 31
2.4.1 Semiconductivity and bandgap structures 31
2.4.2 Transport properties and photovoltaics 37
2.4.3 Laser physics 54
2.4.4 Light-emitting diodes 60
2.4.5 Photodetectors 65
2.4.6 Ferroelectricity and Rashba effect 69
2.4.7 Mechanical properties 73
2.4.8 Thermal conductivity 78
2.4.9 Caloric effects 80
2.4.10 Other properties 82

3 Hybrid formate perovskites 92
3.1 Synthesis and chemical diversity 92
3.2 Symmetries and structures 95
3.3 Phase transitions and order-disorder 103
3.4 Physical properties 107
3.4.1 Magnetism 107
3.4.1.1 Spin-canting and JT effect 107
3.4.1.2 Spin-flop 113
3.4.1.3 Quantum tunneling 116
3.4.2 Dielectricity...