New rare-earth metal germanides with bismuth substitution. Synthesis, structural variations, and magnetism of the RE[BixGe1−x]2 (RE=Y, Pr, Nd, Sm, Gd-Tm, Lu) compounds

► RE[BixGe1−x]2 (RE=rare-earth metal) are the first compounds of the respective elements. ► Their structures are closely related. ► Three structures can be distinguished based on the packing of the REGe6 triangular prisms. ► All compounds show low-temperature antiferromagnetic ordering.