Molybdenum iodides are prepared based on a new way of synthesis, namely, via reductive metathesis reaction of MoCl5 with SiI4. MoI3 was formed at 150 degrees C. Mo6I12 and the new molybdenum iodides Mo6I16 and Mo6I18 with the well-known [Mo6I8](4+) cluster core were obtained in the temperature range 550-600 degrees C. Compounds were structurally characterized by powder and single-crystal X-ray diffraction techniques.