Crystal structure of R3Ge1+xSe7 (R = La, Ce, Pr, Sm, Gd and Tb, x = 0.43–0.49) and magnetic properties of Ce3Ge1.47Se7

The crystal structures of ternary compounds R3Ge1+xSe7 (Dy3Ge1.25S7 structure type, space group P63, Pearson symbol hP22 + 2x, a = 10.7656(7) Å, с = 6.0801(5) Å, R1 = 0.0186 for La3Ge1.48Se7; a = 10.684(1) Å, с = 6.0611(8) Å, R1 = 0.0257 for Ce3Ge1.47Se7; a = 10.6408(9) Å, с = 6.0548(7) Å, R1 = 0.0290 for Pr3Ge1.49Se7; a = 10.4419(7) Å, с = 6.0283(6) Å, R1 = 0.0201 for Sm3Ge1.48Se7; a = 10.325(7) Å, с = 6.0506(7) Å, R1 = 0.0269 for Gd3Ge1.45Se7; a = 10.2747(7) Å, с = 6.0743(5) Å, R1 = 0.0499 for Tb3Ge1.43Se7) were determined by means of X-ray single-crystal diffraction. The R atoms occupy trigonal prisms capped with two additional atoms. The Ge atoms are located in octahedral and tetrahedral environment. The compound Ce3Ge1.47Se7 exhibits a Curie–Weiss type paramagnetic behavior due to the presence of fairly stable local magnetic moments on cerium ions. No hint at any magnetic phase transition was observed down to 1.72 K.

Research highlights▶ Determination and refinement of the crystal structures of R3Ge1+xSe7 (R = La, Ce, Pr, Sm, Gd and Tb, x = 0.43–0.49) compounds from single-crystal X-ray diffraction data ▶ Determination of the magnetic behavior in single-crystalline Ce3Ge1.47Se7.