NEW CRYSTAL-STRUCTURE MAPS FOR INTERMETALLIC COMPOUNDS

New crystal structure maps have been proposed on the basis of the DV-X , molecular orbital calculations of electronic structures. Two electro nic parameters have been introduced and employed as new parameters for the classification of crystal structures. One is the bond order and t he other is the d-orbital energy level of elements. Both of them chang e following the position of elements in the periodic table. With these parameters crystal structure maps have been constructed for aluminide s, silicides, and some transition-metal-based compounds. There is a cl ear separation of the crystal structures on the maps. These maps are f ound to be applicable to the prediction of crystal structures not only for binary compounds but also for ternary compounds. The possibilitie s of structural modification of Nb3Al and Al3Ti by alloying are also d iscussed with the aid of these maps.