Syntheses, crystal structures and magnetic properties of ternary rare-earth zirconium selenides, Ln₂ZrSe₅ (Ln = Ce–Nd)

Three new ternary rare-earth zirconium chalcogenides, Ce₂ZrSe₅ (1), Pr₂ZrSe₅ (2) and Nd₂ZrSe₅ (3), have been synthesized by a facile solid-state route with boron as the reducing reagent. They crystallize in the space group Pnma of the orthorhombic system, belonging to the U₃Se₅ structure type. Their 3-D structures are constructed by parallel polyanionic {[ZrSe₅]^6–}_n chains and LnSe₈ bicapped trigonal prisms. The magnetic susceptibilities' data indicate their antiferromagnetic-like behavior without magnetic order down to 2 K. The structural relationships among several similar structures are discussed, together with the lanthanide contraction in the Ln₂ZrSe₅ system. - Highlights: • Single-crystals of ternary selenides Ln₂ZrSe₅ (Ln = Ce–Nd) were synthesized. • Magnetic susceptibility data were studied. • Comparison between Ln₂ZrSe₅ and related compounds' crystal structures. • Lanthanide contraction among Ln₂ZrSe₅ (Ln = La–Nd, Sm, Gd and Tb).