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

• 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).

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.