Osmium, discovered in 1803, is a rare element with many physical and chemical properties and is used in a variety of applications. In this book, osmium is looked at as an emerging anthropic polluting traffic-related metal. In the second chapter, homoleptic osmium cyanide complexes are explored, particularly their synthesis and applications in molecular magnetism. The third chapter focuses on the synthesis and mixed-valence state of binuclear osmocene derivatives. In the fourth and final chapter, photoneutron cross sections on naturally present osmium isotopes are reviewed.