7440-04-2 Usage
Description
Osmium is a silvery white, hard transition metal with a high melting point and is one of the rarest elements on Earth. It was discovered by English chemist Smithson Tennant in 1804 and named after the Greek word "osme," which means a smell, due to the pungent and peculiar odor of its volatile oxide. Osmium is always associated with other platinum group metals in nature and is usually found in lesser abundance than other noble metals. Its most important mineral is osmiridium (or iridosmine), a naturally occurring mineral alloyed with iridium.
Uses
1. Used in Manufacturing Industry:
Osmium is used as an alloy in the manufacturing of devices that resist wear and stand up to constant use. The reason for this application is that its alloys are very hard, making them suitable for creating items such as ballpoint and fountain pen tips, needles for record players, and pivot points for compass needles.
2. Used in Electrical and Electronic Industry:
Osmium is used as a contact point on special switches and other devices that require reduced frictional wear. This is due to the durability and hardness of osmium alloys, which help in maintaining the performance and longevity of these devices.
3. Used in Scientific Research:
Osmium is used as a stain for animal tissues that are to be examined with a microscope to improve the contrast of the specimen. This application takes advantage of osmium's ability to enhance the visibility of microscopic structures, aiding researchers in their studies.
4. Used in Analytical Chemistry:
Osmium, in the form of plasma standard solution, is used as a standard solution in analytical chemistry and atomic absorption spectroscopy. It is also used as a single-element standard solution for plasma emission spectrometry. This application leverages osmium's properties to ensure accurate and reliable measurements in various chemical analyses.
5. Used in Catalysis:
Osmium exhibits effective catalytic properties in hydrogenation and other organic reactions. However, its use in this area is limited, as it fails to replace other noble metals like palladium and platinum, which are more effective as catalysts and cost less.
Isotopes
Osmium has 41 isotopes, five of which are stable. Two are naturally radioactiveisotopes with very long half-lives. Following are the stable isotopes and their contributionto the element’s natural existence in the Earth’s crust: Os-187 = 1.6%, Os-188 =13.29%, Os-189 = 16.21%, Os-190 = 26.36%, and Os-192 = 40.93%. The remain ing percentage of the element on Earth is in the form of the two naturally radioactiveisotopes: Os-184 = 0.02% and Os-186 = 1.59%. All the other isotopes of osmium areradioactive and artificially produced in nuclear reactors and particle accelerators.
Origin of Name
Its name is derived from the Greek word osme, meaning “odor” or
“smell,” because of the element’s objectionable smell when it is first isolated from platinum
ores using aqua regia.
Characteristics
Osmium is found in group 8 (VIII) of the periodic table and has some of the same chemical,physical, and historical characteristics as several other elements. This group of similarelements is classed as the platinum group, which includes Ru, Rh, and Pd of the second transitionseries and Os, Ir, and Pt of the third series of transition metals .
History
Discovered in 1803 by Tennant in
the residue left when crude platinum is dissolved by aqua regia.
Osmium occurs in iridosmine and in platinum-bearing river sands of the Urals, North America, and South America.
It is also found in the nickel-bearing ores of the 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 high temperatures. It has the highest
melting point and the lowest vapor pressure of the platinum
group. The metal is very difficult to fabricate, but the powder
can be sintered in a hydrogen atmosphere at a temperature
of 2000°C. The solid metal is not affected by air at room temperature,
but the powdered or spongy metal slowly gives off
osmium tetroxide, which is a powerful oxidizing agent and has
a strong smell. The tetroxide is highly toxic, and boils at 130°C
(760 mm). Concentrations in air as low as 10–7 g/m3 can cause
lung congestion, skin damage, or eye damage. The tetroxide
has been used to detect fingerprints and to stain fatty tissue
for microscope 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. The price of 99.9% pure osmium
powder — the form usually supplied commercially — is
about $100/g, depending on quantity and supplier. Natural
osmium contains seven isotopes, one of which, 186Os, is radioactive
with a very long half-life. Thirty-four other isotopes
and isomers are known, all of which are radioactive. 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 22.61 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.
Production Methods
Osmium is obtained in the reaction of osmium tetroxide
(OsO4) reduction with carbon at red heat temperature.
Osmium is also obtained from osmiridium. After separation
from other metals with aqua regia, osmiridium is distilled
in chlorine stream with formation of osmium tetrachloride
(OsCl4), from which the metal is recovered by
reduction.
Hazard
Most of the oxides of osmium are not noxious, but are toxic if inhaled or ingested. Thecompound OsO4 is extremely poisonous. It is a powerful oxidizing agent that is soluble inwater and will produce serious burns in skin as it oxidizes the various layers of tissues.
Safety Profile
Poison by intravenous route. An irritant to eyes and mucous membranes. The principal effects of exposure are ocular disturbances and an asthmatic condition caused by inhalation. Furthermore, it causes dermatitis and ulceration of the skin upon contact. When osmium is heated, it gives off a pungent, poisonous fume of osmium tetroxide. One case of osmium poisoning reported in the literature resulted from the inhalation of osmium, which gave rise to a capillary bronchitis and dermatitis. The tetroxide vapor has a pronounced and nauseating odor that should be taken as a warning of a possibly toxic concentration in the atmosphere, and personnel should immedately move to an area of fresh air. The metal itself is not highly toxic. Flammable in the form of dust when exposed to heat or flame. Slight explosion hazard in the form of dust when exposed to heat or flame. Violent reaction or ignition with chlorine trichloride or oxygen dfluoride. Ignites when heated to l00℃ with fluorine. Incandescent reaction in phosphorus vapor. When heated to decomposition it emits toxic fumes of 0s04. See also OSMIUM TETROXIDE
Check Digit Verification of cas no
The CAS Registry Mumber 7440-04-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,4,4 and 0 respectively; the second part has 2 digits, 0 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 7440-04:
(6*7)+(5*4)+(4*4)+(3*0)+(2*0)+(1*4)=82
82 % 10 = 2
So 7440-04-2 is a valid CAS Registry Number.
InChI:InChI=1/Os
