Osmium Tetroxide

Osmium tetroxide (also called osmium tetraoxide) is the chemical compound with the formula OsO4. The compound is noteworthy for its many uses, despite the rarity of osmium. It also has a number of interesting properties, one being that the solid is volatile. The compound is colourless, but most samples appear yellow.

Read more about Osmium Tetroxide:  Physical Properties, Structure and Electron Configuration, Synthesis, Safety Considerations