Single crystal refinements of TbTiGe, GdTiGe and TbTi0.85Mo0.15Ge with CeFeSi- and CeScSi-type structures

The atomic coordinates of the TbTi0.85Mo0.15Ge, GdTiGe and TbTiGe compounds have been refined from single crystal X-ray diffraction measurements. Both former compounds have a tetragonal CeScSi-type structure (I4/mmm, ordered variant of the La2Sb-type) while TbTiGe crystallizes in the CeFeSi-type (P4/nmm). The structural properties and the relative stability of both CeFeSi and CeScSi-type structures along the whole RTiGe series (R=La-Nd, Sm, Gd-Tm, Lu) are discussed and compared to those of others isotypic RTX compounds.