Osmium is a rare chemical element belonging to the Platinum Group Metals (PGMs). This silver-grey, shiny metal resists corrosion and is the densest of all chemical elements. In fact, it is twice as dense as lead. It is largely used as an alloy agent with platinum, iridium’s and other PGM metals.
In the medical field, osmium has exhibited a vast potential of treating various types of cancer, including colon and ovarian cancers, which have been processed and tested at the laboratory. Today, the purpose is to explore other applications of this rare metal, besides the treatment of cancer.
What is Osmium Used For?
It is important to note that osmium is hardly used its pure form, primarily because it can be extremely toxic and volatile. It’s often alloyed with other metals for commercial applications. Some of the common uses of osmium include:
- Fingerprint’s detection
- Light bulb technology
- Fountain pen tips
- Instrument Pivots
- Defense ammunition
- Industrial moldings
- Staining fatty tissue for microscopy
Applications of Osmium in Fingerprint Detection and Fatty Tissue Staining
Osmium tetroxide is an oxidant that uses cross lipids and through its reaction with carbon bonds fixes organic membranes in place in tissue samples, simultaneously staining them. Owing to the fact that osmium atoms are tremendously electron dense, osmium staining significantly enhances in Transmission Electron Microscopy – TEM – studies of biological substances. Osmium ferricyanide – OsFeCN – is another osmium compound that exhibits similar fixing and staining effects.
The tetroxide and potassium osmatic (a related compound) are vital oxidants for chemical synthesis. In fact, Karl Barry Sharpless won the Nobel Prize in Chemistry for his Sharpless asymmetric dihydroxylation that utilizes osmate for the transfiguration of a double bond into a vicinal diol. However, osmate tetroxide is quite costly for this application, and hence potassium permanganate is often used instead, but with lesser yields.
Light Bulb Technology
The history of the light-bulb dates back to 1898 when Auer von Welsbach, an Austrian chemist devised the Oslamp with an osmium-made filament. Welsbach introduced this lamp commercially in 1992. Osmium would later be replaced by the more stable and reliable metal tungsten. Tungsten boasts the highest melting point compared to any other metal.
As such, using tungsten in light bulbs enhances the luminous value and life of incandescent lamps. Osram, the light bulb manufacturer founded in 1906, derives its name from the components of osmium and wolfram. Wolfram is German term for tungsten.
Powdered osmium is effective in the use of battery electrodes as it absorbs hydrogen ions absorbing hydrogen ions. The only drawback is that osmium is quite costly and might react with potassium hydroxide, which is the most popular battery electrolyte.
Osmium boasts a high reflectivity in the UV range of the electromagnetic spectrum. For instance, at 600Å it has a reflectivity that’s two times that of gold. This great reflectivity is necessary in space-based UV spectrometers that have minimized mirror sizes, thanks to space limitations. Mirrors coated with osmium were flown in a number of space missions aboard the Space Shuttle. However, it soon became obvious that the oxygen radicals in the lower earth orbit are so much that they can significantly damage the osmium layer.
In the medical industry, osmium was also used for synovectomy in arthritic patients. Synovectomy encompasses the local administration of osmium tetroxide, which is an extremely toxic compound. The fact that there are no reports showing long-term side effects, points towards osmium being biocompatible. However, this is determined by the osmium compound administered.
Osmium alloys, such as osmiridium, are extremely hard and hence used in high-wear applications. They are used in the making of instrument pivots, fountain pen nibs, as well as electrical contacts, since they can resist wear from everyday usage. In fact, osmium alloy tips are more hard-wearing compared to chromium and steel tips. However, they are not as durable as diamond and sapphire tips.
Osmium is a rare metal element, which is highly volatile and extremely toxic. As such, it is hardly used in its pure state, but usually alloyed with other metals. It has limited uses. In 2011, osmium (VI) and osmium (II) reportedly exhibited anticancer activity in vivo. This indicated a bright future for using osmium pounds in the treatment of cancer. Other beneficial uses of osmium include manufacture of needles, electrical contacts, fountain pen nibs, and instrument pivots. Osmium can also be used as a catalyst in industrial chemical reactions.