EVIDENCE FOR NEW PHASES IN THE ZR, LN-RU- P SYSTEMS

Crystallochemical analysis of the binary compounds square(2)Cr(12)P(7) and square(6)Rh(20)Si(13) prompted us to introduce rare earth element s and zirconium into the trigonal prismatic metalloids in order to obt ain ternary compounds. Our current study of the Zr, Ln-Ru-P systems sh ows the existence of many new ternary phosphides of formulae (Zr, La)( 2)RU12P7, (ZT, La)(5)RU19P12. (Zr, Ln)(6)Ru20P13 (Ln = La, Ce, Pr, Nd, Sm and Y) and La20Ru66P43 All Of them crystallize in the hexagonal la ttice with structures of different arrangements derived from the same basic rhombohedral motif. The differences amongst these arrangements r esult from the introduction of different proportions of various metall ic elements.