Investigations made by powder X-ray diffraction on four new ternary LuTiSi, LuTiGe, ZrVGe and HfVGe compounds are reported. The compounds LuTiSi (a=0.3974(1) nm, c=0.7379(1) nm) and LuTiGe (a=0.3992(1) nm, c=0.7446(1) nm) crystallize in the tetragonal CeFeSi-type structure (space group P4/nmm). The compounds ZrVGe (a=0.3754(1) nm, c=1.4488(1) nm) and HfVGe (a=0.3725(1) nm. c=1.4346(2) nm) crystallize in the tetragonal CeScSi-type structure (space group I4/mmm). (C) 1999 Published by Elsevier Science S.A. All rights reserved.