STRUCTURAL, MOSSBAUER SPECTROSCOPIC AND MAGNETOCHEMICAL INVESTIGATIONS INTO EUPT5, TMPT5 AND TMPT3 SYNTHESIZED FROM PLATINUM AND GASEOUS LANTHANIDE

EuPt5, TmPt5, and TmPt3 were prepared by reaction of the gaseous lanth anides with Pt at 1200, 1300, and 1500 degrees C respectively. Structu ral investigations established that the former two crystallize in CaCu 5-type related superstructures, the details being still under investig ation. Eu-151 Mossbauer spectroscopy and magnetic susceptibility measu rements revealed that EuPt5 is a mixed-valent europium alloy containin g both trivalent (Eu[4f(6)]) and intermediate-valent Eu, the latter as a dynamic mixture of the [4f(6)] and [4f(7)] configurations. The magn etochemical analysis of TmPt3 (AuCu3-type structure) on the basis of a crystal field/molecular held model disclosed trivalent Tm[4f(12)] wit h a singlet crystal field ground state and the absence of magnetic ord ering (for T greater than or equal to 1.7 K).