ELF and chemical bonding in intermetallic compounds
Yuri Grin, MPI for Chemical Physics of Solids, Dresde, R.F.A.
e-mail: grin@cpfs.mpg.de
Jeudi 10 mai 2001, 11h00
Caused by the strongly application impressed development of the knowledge on
intermetallic compounds, the understanding of their nature fell behind. We still
can not definitely answer important questions, why the intermetallic compounds
form only at distinct compositions, why and under which conditions they build
homogeneity ranges and finally why some structural motifs are extremely stable
and can be often found among the intermetallics, while others appear very rare.
One reason for this situation is surely insufficient knowledge about chemical
bonding in intermetallic compounds, because the common bond models prefer
either a ionic-covalent or a metallic interpretation of the bonding situation.
Recently, the Electron-Localization-Function (ELF) is going to be developed to
a useful quantum-chemical tool for investigation of the problem of the directed
bond formation in compounds with typically metallic physical properties
(conductivity, lustre, magnetism). The efforts and problems of the use of ELF
for the description of the chemical bonding in intermetallic compounds are
discussed on examples from different compound groups: clathrates, binary compounds
of transition metals and some rare earth metals phases.