Synthesis, crystal and electronic structures of Pt-rich phosphides EuPt3P and EuPt6P2

Abstract

Two new ternary Pt-rich phosphides, EuPt₆P₂ and EuPt₃P, have been prepared via a two-step solid state reaction. Their crystal structures have been determined from powder XRD data. EuPt₆P₂ is isostructural to SrPt₆P₂ (cubic, Pa, a = 8.4603(1) Å); its crystal structure comprises corner-sharing Pt₆P trigonal prisms hosting Eu²⁺ cations in the cuboctahedral voids of the framework. EuPt₃P is isostructural to the SrPt₃P anti-perovskite (P4/nmm, a = 5.7452(1) Å and c = 5.4212(1) Å). Magnetization measurements reveal the magnetic response caused by the Eu²⁺(4f⁷) cations. EuPt₆P₂ is paramagnetic exhibiting no phase transitions down to 1.8 K, whereas EuPt₃P orders ferromagnetically below 19 K. Similar to SrPt₆P₂ and SrPt₃P, the new compounds are metallic with states near the Fermi level predominantly formed by the 5d orbitals of Pt.