»ã±¨±êÌ⣺½ðÊô¼ä»¯ºÏÎ´Ó»¯Ñ§¼üµ½»úÄÜ
      Intermetallic Compounds: from Chemical Bonding to Useful Properties
»ã±¨ÄÚÈݼò½é£ºIntermetallic compounds show physical properties interesting for applications, serving therefore as important components for materials design. An attempt to find a direct link between the properties and the crystal structure as well the atomic interactions for this group of inorganic substances leads not seldom to the conclusion, that there is a lack of reliable information on all three, crystal structure, bonding and properties, hindering studies on their relationship. Especially, chemical bonding in intermetallic compounds and its relation to the crystal structure is a rather open question. An application of Electron Localizability approach (ELI-D) opens access to the bond definition in real space, allows revealing of the – on first glance unexpected - relation between organometallic and intermetallic compounds and gives a possibility of Zintl-like electron counting for large group of intermetallic phases. This – in turn – yields a connection to the basic information about the band structure. The intermetallic clathrates attract the attention of material’s developers during the past decades due to their promising thermoelectric activity. The ELI-D approach allows differentiation of covalent and ionic contributions to the atomic interactions. With the new tools the formation of the lone pairs around the defects in the Ge framework in Ba8Ge43□3 was revealed, and the covalent Ba-Au interactions were detected in the clathrate Ba8AuxGe46-x-y□y. Both findings yield to the special features of the electronic DOS, which were confirmed by measurements of electronic and thermal transport. Bonding-caused features in the real structure of TmAlB4 yield new magnetic interactions and remarkable difference in the magnetic properties between the ideal and real material. Understanding of the bonding in intermetallic clathrates opens a way to novel redox-based preparation routes. So the hitherto unknown binary clathrates BaGe5, ternary clathrate Ba8Ni3.5Ge42.1□0.4 or the prototype of clathrate-II – Na24Si136 – were prepared and their transport properties were investigated. Another recent bonding-based concept dealing with the intermetallic phases is isolated-site model for catalysis. New catalysts for semi hydrogenation of acetylene – based on the well-crystallized intermetallic compounds GaPd and Al4Fe13 – were suggested employing the ideas of the covalent atomic interactions in intermetallic compounds.
»ã±¨ÈËÐÕÃû£ºYuri Grin
»ã±¨È˼ò½é£ºµÂ¹úÂíÆÕ¹ÌÌ廯ѧÎïÀíËùËù³¤¡¢½ÌÊÚ£¬µÂ¹úµÂÀÛ˹¶Ù¹¤Òµ´óѧ½ÌÊÚ
      Director and Professor of Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden; Professor of Dresden Technical University£¬ Germany
»ã±¨È˵¥Ôª£ºµÂ¹úÂíÆÕ¹ÌÌ廯ѧÎïÀíËù£¬µÂ¹úµÂÀÛ˹¶Ù¹¤Òµ´óѧ
     Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden
»ã±¨¹¦·ò£º2014-03-31 09:00
»ã±¨µØÖ·£ºÐ±¦GGУ±¾²¿¶«Çø×ÊÁÏÂ¥520»áÒéÊÒ