Preparation, Structure and Properties of New Ternary Chalcogenides and Germanides of the Metals from the First Transition Series, Cr, Mn, Fe and Ni DISSERTATION zur Erlangung des Grades eines Doktors der Naturwissenschaften vorgelegt von Dipl. Ing. – Chem. Krasimir Aleksandrov geb. am 03.12.1975 in Vratsa eingereicht beim Fachbereich 8 der Universität Siegen Siegen 2005 Berichterstatter: Prof. Dr. H. -J. Deiseroth Prof. Dr. H. Haeuseler Tag der mündlichen Prüfung: 30.06.2005 urn:nbn:de:hbz:467-1058 Acknowledgements This work was completed during the time from June 2001 to May 2005 in the Inorganic Chemistry Department, University of Siegen under the guidance of Prof. Dr. H. J. Deiseroth. I would like to express my heartfelt gratitude to my supervisor Prof. Dr. H. J. Deiseroth for his elaborate guidance and unlimited enthusiasm. I would like to thank Dr. C. Reiner for our many fruitful discussions and SEM investigations and Dr. M. Schlosser for the single crystal measurements. I am also very gratefully to both Dipl. Chem. J. Schlirf and Dr. M. Aleksandrova for their assistance in carrying out the DTA and IR measurements. I would like to thank my colleagues Dipl. Chem. Michael Wagener, Dipl. Chem. Kledi Xhaxhiu and all the other members of the Inorganic Chemistry group of the University of Siegen, with whom I had the pleasure of working. I am especially pleased to acknowledge the assistance of Dipl. Ing. W. Büdenbender in the technical problems. I would like to thank Dr. R. K. Kremer from the Max – Planck – Institute for Solid State Research, Stuttgart for carrying out the magnetic measurements. Finally, I would especially like to thank my wife Margarita and our son Ivan as well as my parents Hristina and Ivan, and my brother Rosen, who were a constant source of encouragement and support. Contents 1 Contents 1 Introduction .................................................................................................................... 4 2 Motivation........................................................................................................................ 5 3 Experimental................................................................................................................... 7 3.1 Preparation procedure................................................................................................. 7 3.2 Vacuum technique....................................................................................................... 8 3.2.1 Vacuum system outline ................................................................................... 8 3.2.2 Evacuation procedure.................................................................................... 10 3.3 X – ray characterization methods.............................................................................. 11 3.3.1 Introduction ................................................................................................... 11 3.3.2 Powder X – ray methods ............................................................................... 13 3.3.3 Single crystal X – ray structure analyse........................................................ 14 3.4 Thermal analysis....................................................................................................... 14 3.5 Scanning electron microscopy .................................................................................. 14 3.6 Infrared spectroscopy................................................................................................ 15 3.7 Magnetic measurements............................................................................................ 16 4 The compound Mn2GeSe4 ........................................................................................ 17 4.1 Introduction ............................................................................................................... 17 4.2 Preparation and properties......................................................................................... 18 4.3 Characterization ........................................................................................................ 21 4.4 Single crystal analysis ............................................................................................... 26 4.5 Structure description and discussion......................................................................... 27 4.6 MAPLE calculations................................................................................................. 32 4.7 Olivine or spinel structure......................................................................................... 34 4.8 Magnetic measurements............................................................................................ 35 Contents 2 5 Cr2Ge2Se6 – a new member of M2X2Y6 compounds mn(M = Transition metal, X = Si, Ge, Y = Chalcogen) ....................................... 37 5.1 Structure – chemical relations................................................................................... 37 5.2 Preparation and properties......................................................................................... 43 5.3 Characterization ........................................................................................................ 46 5.4 Outlook...................................................................................................................... 50 6 M3GeTe2 compounds (M = Fe, Ni)........................................................................ 51 6.1 Introduction ............................................................................................................... 51 6.2 The compound Fe3GeTe2 .......................................................................................... 52 6.2.1 Preparation and properties............................................................................. 52 6.2.2 Characterization ............................................................................................ 55 6.2.3 Single crystal analysis ................................................................................... 57 6.2.4 Structure description and discussion............................................................. 58 6.2.5 Magnetic measurements................................................................................ 65 6.3 The compound Ni3GeTe2 .......................................................................................... 67 6.3.1 Preparation and properties............................................................................. 67 6.3.2 Characterization ............................................................................................ 70 6.3.3 Single crystal analysis ................................................................................... 75 6.3.4 Structure description and discussion............................................................. 76 6.3.5 Magnetic measurements................................................................................ 82 7 Synthesis and characterisation of nanoscale hydroxylapatite .................... 83 7.1 Introduction ............................................................................................................... 83 7.2 Experimental outline................................................................................................. 84 7.3 Results and discussion............................................................................................... 85 7.3.1 IR characterization........................................................................................ 85 7.3.2 X – ray characterization ................................................................................ 91 7.3.3 SEM investigation......................................................................................... 93 7.3.4 Influence of the temperature ......................................................................... 97 7.3.5 Conclusion................................................................................................... 100 Contents 3 8 Preliminary experiments to synthesise new ternary transition metal chalcogenides .................................................................................................. 102 8.1 Research on transition metal olivines, A2BX4 Lkdfgj (A = transition metal, B = Si, Ge, Sn, X = Se, Te).................................................. 102 8.2 Attempts to prepare ternary compounds of the type M2X2Y6 Lssdlf (M = transition metal, X = Si, Ge, Sn, Y = S, Se, Te) ............................................ 105 8.3 Research on M3BX2 compounds Kljf (M = transition metal, B = Si, Ge, Sn, X = Se, Te) ................................................. 108 9 Summary ...................................................................................................................... 110 10 References .................................................................................................................... 113 11 Appendix ...................................................................................................................... 131 11.1 Data for Mn2GeSe4.................................................................................................. 131 11.2 Data for Cr2Ge2Se6 .................................................................................................. 135 11.3 Data for Fe3GeTe2 ................................................................................................... 137 11.4 Data for Ni3GeTe2 ..................................................................................................