Osmium Tetroxide

Osmium tetroxide, also known as osmium(VIII)-oxide, has the chemical formula OsO4 and is a compound of the elements osmium and oxygen, in which osmium is present in its highest oxidation state (+8). It is primarily used as a homogenous catalyst and microscopic agent.

How can I purchase osmium tetroxide?

Heraeus offers osmium tetroxide crystals and osmium tetroxide solution in small quantities for research projects as well as large quantities for industrial applications. Due to our decades of experience in the extraction and processing of osmium, we can guarantee you a high and consistent quality of our osmium tetroxide.

If you are interested in obtaining our osmium tetroxide in larger amounts, please use the request for quote function within our shop. We will contact you as soon as possible to discuss your exact requirements. Our mission is not only to offer custom solutions but to consult and work together with our clients so they can achieve the best results possible.

If you want to obtain samples of our osmium tetroxide quickly and effortlessly, please visit our shop as well. There, you can also find our safety data sheet and product specifications of any of our chemical compounds and products.

What properties does osmium tetroxide have?

Osmium tetroxide consists of monoclinic yellowish crystals with an osmium content of 74-76 percent. Osmium tetroxide is a corrosive, very toxic compound which, due to its hazard class and volatility (sublimates at room temperature), is most commonly sold in sealed glass ampoules.

Osmium(VIII)-oxide has an acrid, chlorine-like odor. The osmium tetroxide molecule is tetrahedral and therefore non-polar. This non-polarity helps OsO4 to penetrate charged cell membranes. OsO4 is approximately 500 times more soluble in carbon tetrachloride than it is in water.

OsO4 is formed slowly when osmium powder reacts with oxygen at room temperature. To produce large quantities, osmium powder is heated to 400 °C under oxygen supply.

The chemical equation is as follows: Os + 2 O2 -> OsO4

Chemical application

Osmium tetroxide is an effective catalyst which is used for its reliability and efficiency in the dihydroxylation of alkenes to produce diols, i.e. organic compounds with two hydroxy groups.

Due to its value and toxicity, only small amounts of OsO4 are usually applied in combination with a stoichiometric oxidant. Osmium tetroxide is most commonly used in Upjohn and Sharpless dihydroxylation reactions.

Upjohn vs. Sharpless dihydroxylation

Both dihydroxylations are similar in their reaction sequence and produce diols. However, in Sharpless dihydroxylation, enantioselectivity is achieved by the addition of chiral ligands: enantiomerically pure diols are produced, which are required for producing active pharmaceutical ingredients.

Industrial application

Due to its catalytic properties, osmium tetroxide is used as a homogeneous catalyst mainly in the production of pharmaceutical and agrochemical active ingredients. With the help of OsO4 new potent pesticides and drugs could be developed.

Besides its catalytic function, osmium tetroxide is also used in microscopy. Thanks to its low polarity, osmium tetroxide can penetrate the cell membrane and fix the lipids. The high electron density of osmium enables high-contrast electron microscopic images of biological samples.