University of Warsaw Faculty of Chemistry Crystal structure and selected physical properties of AgO, AgF2 and AgClx phases under high pressure Adam Grzelak Doctoral dissertation developed in 2014 – 2018 at Laboratory of Technology of Novel Functional Materials under the supervision of Prof. Wojciech Grochala Warsaw, June 2018 Acknowledgments First of all, I would like to thank my thesis supervisor Prof. Wojciech Grochala for assigning me an interesting and challenging topic of research, for valuable discussions, which allowed me to gain a deeper understanding of chemistry and physics, and for constantly presenting me with numerous opportunities, which enabled me to learn new skills that I hope to use in my future scientific endeavors. I am very grateful to Dr Viktor Struzhkin from Carnegie Insitution of Washington, who taught me the essential principles of high-pressure experiments, including preparation of DAC systems, sample loading and X-ray diffraction measurements using synchrotron sources. I would also like to thank Dr Maddury Somayazulu for his help with preparation of Ag/Cl systems under high pressure. In addition, I would like to thank Jakub Gawraczyński, with whom I performed and later analyzed results of many of those experiments. I would like to thank Dr Mariana Derzsi for performing theoretical calculations, which proved indispensable for understanding experimental results and provided insight into physical properties of materials studied in this work, as well as for teaching me the technicalities of density functional theory calculations. I would like to express my gratitude to all members of Laboratory of Technology of Novel Functional Materials for creating a positive and encouraging working environment. I would especially like to acknowledge contributions from the following members of LTNFM: - Dr Tomasz Jaroń for his guidance through experimental details of high-pressure electrical resistance measurements; - Dr Dominik Kurzydłowski for valuable discussions, helpful comments and sharing resources and knowledge about chemistry of transition metal compounds; - Dr Piotr Leszczyński for the help with finding essential literature; - Fellow PhD students Jakub Gawraczyński, Agnieszka Starobrat, Rafał Owarzany, Wojciech Wegner and Piotr Orłowski for the shared experience of becoming a scientist and for their friendship extending well beyond work hours. I would like to thank my Mother for her continued support during my doctoral studies, without which I would not have been able to finish this work. I am also grateful to all my friends and family for supporting and motivating me throughout the writing process. i Financial contributions Studies presented in this work were funded by the following sources: “HP” project from Polish National Science Center (NCN), grant no. 2012/06/M/ ST5/00344, led by Prof. Wojciech Grochala Research program no. P1-0045 Inorganic Chemistry and Technology from Slovenian Research Agency (ARRS), led by Dr Zoran Mazej Calculations performed by Dr Mariana Derzsi were carried out using ADVANCE-PLUS supercomputer under grant no. GA67-13 at Interdisciplinary Center for Mathematical and Computational Modelling (ICM), led by Prof. Wojciech Grochala X-ray diffraction studies were performed using two Advanced Photon Source facilities (a U.S. Department of Energy (DOE) Office of Science User Facility, operated for the DOE Office of Science by ANL under Contract DE-AC02-06CH11357) at Argonne National Laboratory: o GSECARS (sector 13), supported by the National Science Foundation (NSF), Earth Sciences (Grant EAR-1128799), and Department of Energy (DOE), GeoSciences (Grant DE-FG02-94ER14466) o HPCAT (sector 16), supported by DOE-NNSA under Award DE-NA0001974 and DOE-BES under Award No. DE- FG02-99ER45775, with partial instrumentation funding by the NSF Electrical resistance measurements of compressed samples of AgF2 were carried out as part of a DSM project funded by the Polish Ministry of Science, grant no. 501-D112-86- DSM-115100, led by myself ii Contents (EN) Abstract ................................................................................................................................. 1 (PL) Streszczenie pracy ................................................................................................................. 3 (EN) Introduction .......................................................................................................................... 5 (PL) Wprowadzenie ....................................................................................................................... 7 (EN) Goals of this work ................................................................................................................ 9 (PL) Cele pracy ............................................................................................................................ 11 Literature review.......................................................................................................................... 13 1. Introductory notes on several physical phenomena in solids .............................................. 13 1.1. Types of magnetic ordering........................................................................................... 13 1.2. Jahn-Teller effect........................................................................................................... 15 1.3. Mott and charge-transfer insulators............................................................................... 17 2. High pressure science .......................................................................................................... 18 2.1. Historical notes .............................................................................................................. 18 2.2. Physical chemistry at high pressures ............................................................................. 20 2.3. Jahn-Teller effect at high pressure ................................................................................ 23 3. Chemistry of silver and its compounds ................................................................................ 25 3.1. Silver ............................................................................................................................. 25 3.2. Chemical properties of silver ........................................................................................ 26 3.3. Chemistry of silver(II) ................................................................................................... 27 3.3.1. Silver(II) fluorides .................................................................................................. 28 3.3.2. Other silver-fluorine systems .................................................................................. 34 3.3.3. Silver(II) compounds – beyond fluorides ............................................................... 36 3.4. Silver-oxygen systems .................................................................................................. 40 3.5. Hypothetical AgClx compounds .................................................................................... 47 4. Overview of relevant analogous compounds and their high pressure behavior .................. 49 4.1. High-pressure behavior of transition metal monoxides ................................................ 49 4.2. High-pressure behavior of mixed-valence compounds ................................................. 58 4.3. High-pressure behavior of transition metal difluorides ................................................. 65 4.4. High-pressure behavior of silver compounds................................................................ 71 5. Overview of experimental methods ..................................................................................... 74 5.1. The diamond anvil cell .................................................................................................. 74 5.2. X-ray diffraction ............................................................................................................ 77 5.3. Electron transport properties ......................................................................................... 83 Experimental results .................................................................................................................... 87 6. Silver(I,III) oxide AgO ........................................................................................................ 87 6.1. Powder X-ray diffraction studies of compressed AgO ................................................. 87 6.1.1. Experimental procedures ........................................................................................ 87 6.1.2. Preliminary analysis of powder XRD patterns ....................................................... 88 6.1.3. High pressure behavior of LP-AgO ........................................................................ 91 iii 6.2. Pressure-induced phase transitions of AgO as determined by powder XRD and theoretical methods .............................................................................................................. 95 6.2.1. LP to HP transition ................................................................................................. 95 6.2.2. Crystal structure and high pressure behavior of HP-AgO ...................................... 97 6.2.3. HP1 to HP2 transition ........................................................................................... 102 6.2.4. Local coordination