Structural, Mössbauer spectroscopic and magnetochemical investigations into EuPt5, TmPt5 and TmPt3 synthesized from platinum and gaseous lanthanide☆

Abstract EuPt 5 , TmPt 5 , and TmPt 3 were prepared by reaction of the gaseous lanthanides with Pt at 1200, 1300, and 1500°C respectively. Structural investigations established that the former two crystallize in CaCu 5 -type related superstructures, the details being still under investigation. 151 Eu Mossbauer spectroscopy and magnetic susceptibility measurements revealed that EuPt 5 is a mixed-valent europium alloy containing both trivalent (Eu[4f 6 ]) and intermediate-valent Eu, the latter as a dynamic mixture of the [4f 6 ] and [4f 7 ] configurations. The magnetochemical analysis of TmPt 1 (AuCu 1 -type structure) on the basis of a crystal field/molecular field model disclosed trivalent Tm[4f 12 ] with a singlet crystal field ground state and the absence of magnetic ordering (for T ≥1.7K).