REACTION OF RARE-EARTH-METALS WITH VI-GROUP AND VII-GROUP TRANSITION-METALS AND BORON

results of experimental investigations of reactions of rare-earth (Ln) and transition (Me-VI,Me- VII) metals with boron were reviewed. An an alysis of the phase equilibrium diagrams of 50 Ln-Me-B systems was car ried our. The laws of formation of ternary borides were determined, an d the characteristics of 12 structural types in which they crystallize described. The coordination and types of boron atom linkage, as well as the valence state of the Ln atoms were considered.