Osmium: From Osmium Sponge to Osmium Tetroxide and a Novel Osmium Compound | Periodic Videos

Osmium and its compounds

This Periodic Videos segment introduces osmium, a heavy platinum group metal, and showcases an osmium sponge sealed in a glass vial. It also discusses how osmium reacts with air to form the volatile and highly toxic osmium tetroxide, underscoring the safety protocols used when handling osmium.

• Osmium is stored under argon to prevent oxidation
• Osmium tetroxide is volatile and has a strong odor, and is highly toxic
• The video recalls early osmium chemistry from the presenter's doctoral work
• A rare osmium compound, osmium dicarbonyl dinitrozyl, is mentioned as a unique synthesis

Osmium Chemistry in Focus

Osmium, a member of the platinum group, is highlighted in this video from Periodic Videos. The host presents an osmium sponge neatly packaged in a box and explains osmium’s position among platinum group metals. The discussion extends to osmium tetroxide, a stable yet highly volatile oxide that readily vaporizes and carries a strong, characteristic odor. This compound is a powerful reagent in organic chemistry for the syn-dihydroxylation of carbon-carbon double bonds, converting alkenes into vicinal diols with notable selectivity. The segment emphasizes safety, noting that OsO4 is extremely toxic and can cause blindness, requiring careful storage and handling.

Handling and Historical Context

Osmium metal is stored in an inert argon atmosphere to prevent oxidation, and the metal appears as a very dark, sponge-like solid at the bottom of a glass vial. The presenter shares memories from an early stage of his career, where osmium compounds were studied alongside ruthenium and iron compounds, each with distinct colors. The osmium compound described in his account was pale yellow and behaved as predicted, though it was considered the most boring of the trio. A notable note is made about the discovery of osmium dicarbonyl dinitrozyl, a compound nobody had made before, which excited him though color information is unavailable due to limited quantities.

Takeaways for viewers

The video offers insight into osmium chemistry, the critical safety considerations surrounding osmium tetroxide, and a glimpse into exploratory inorganic synthesis. It illustrates how a single element can reveal a wide range of chemistry from a stable sponge form to volatile oxides, and even to novel compounds under careful synthetic conditions.