My Saved Article
For fountain pen points.
|Atomic Number:||76||Atomic Symbol:||Os|
|Atomic Weight:||190.2||Electron Configuration:||2-8-18-32-14-2|
|Melting Point:||3045oC||Boiling Point:||5027oC|
|Description:||Hard fine black powder or hard blue-gray mass.|
|Uses:||Used to tip gold pen points,to make standard weights |
and electric light filaments.
History(Gr. osme, a smell) Discovered in 1803 by Tennant in the residue
left when crude platinum is dissolved by aqua regia.
- Osmium occurs in iridosule and in platinum-bearing river sands of the Urals,
North America, and South America.
- It is also found in the nickel-bearing ores of Sudbury, Ontario region along
with other platinum metals.
- While the quantity of platinum metals in these ores is very small, the large
tonnages of nickel ores processed make commercial recovery possible.
- The metal is lustrous, bluish white, extremely hard, and brittle even at
- It has the highest melting point and the lowest vapor pressure of the
- The metal is very difficult to fabricate, but the powdered or spongy metal
slowly gives off osmium tetroxide, which as a powerful oxidizing agent and has a
- The tetroxide is highly toxic, and boils at 130C.
- Concentrations in air as low as 10^7 g/m^3 can cause lung congestion, skin
damage, or eye damage.
- Exposure to osmium tetroxide should not exceed 0.0016 mg/m^3 (8-hour time
weighted average - 40-hour work week).
- The tetroxide has been used to detect fingerprints and to stain fatty tissue
for miscroscope slides.
- The metal is almost entirely used to produce very hard alloys, with other
metals of the platinum group, for fountain pen tips, instrument pivots,
phonograph needles, and electrical contacts.
CostsThe price of 99% pure osmium powder - the form usually supplied
commercially - is about $100/g, depending on quantity and supplier.
- The measured densities of iridium and osmium seem to indicate that osmium is
slightly more dense than iridium, so osmium has generally been credited with
being the heaviest known element.
- Calculations of the density from the space lattice which may be more
reliable for these elements than actual measurements, however, give a density of
22.65 for iridium compared to 22.661 for osmium.
- At present, therefore, we know either iridium or osmium is the heaviest
element, but the data do not allow selection between the two.