Synthesis of Highly Magnetic, Air-Stable Iron–Iron Carbide Nanocrystalline Particles by Using Power Ultrasound A. Gedanken is grateful for the support of the German Ministry of Science through the Deutsche-Israeli DIP program. I. Felner and A. Gedanken thank also the Israeli Ministery of Science, Culture and Sport for an infrastructure grant. S. I. Nikitenko thanks the Bar-Ilan Research Authority for his fellowship. The authors also thank Dr. Shifra Hochberg for editorial assistance.