Flux Crystal Growth of a Series of Potassium Lanthanide Germanates: K <i>Ln</i> Ge ₂ O ₆ ( <i>Ln</i> = Pr, Nd, Sm–Dy)

A series of potassium lanthanide germanates, K Ln Ge 2 O 6 ( Ln = Pr, Nd, Sm–Dy), were synthesized by flux crystal growth. Single-crystal structures were determined for all seven compositions. The series crystallize in the monoclinic space group C 2/ c . The lanthanide cations occupy, in a 2:1 ratio, octahedral and bicapped trigonal-prismatic coordination environments and connect via edge-sharing to form infinite chains. The chains are linked via Ge 3 O 3 O 6/2 units to create a 3D structure. The magnetic properties of the Nd-containing member and the optical properties of the Eu- and Tb-containing members were investigated. The luminescence behavior of KEuGe 2 O 6 is consistent with that of previous reports. Thermal stability was explored by using high-temperature powder X-ray diffraction.