Osmiumtetroxid

Osmiumtetroxid, commonly known as osmium tetroxide (OsO4), is a volatile, highly toxic inorganic compound of osmium in the +8 oxidation state. It appears as yellow to orange crystals that readily sublime at room temperature and has a distinctive, pungent odor often described as ozone-like. OsO4 is a strong oxidizer and responds readily with water and organic compounds, forming various osmium-containing species.

In use, osmium tetroxide serves two main roles. In electron microscopy, it is employed as a stain to provide contrast for lipid membranes and related structures, helping to visualize cellular components. In organic synthesis, OsO4 facilitates syn-dihydroxylation of alkenes to yield vicinal diols; this transformation can be performed on a catalytic basis with a co-oxidant, using only small amounts of OsO4.

Production and handling are conducted under stringent safety controls due to its toxicity and volatility. Osmium tetroxide is typically generated and used in specialized laboratory settings, with appropriate ventilation and personal protective equipment. Inhalation or skin contact can cause severe respiratory irritation and tissue damage; exposure can also affect the eyes and may lead to longer-term health effects. Because of these hazards, handling is restricted to trained personnel, and waste is disposed of following strict regulatory guidelines. Quenching spills with suitable reducing agents is standard practice to deactivate remaining OsO4.

Due to its toxicity and cost, osmium tetroxide is generally limited to laboratory and specialized industrial applications, where controlled conditions and proper safety measures are in place.