PRODUCT NAME: OSMIC ACID
CAS NO:20816-12-0
FORMULA :OsO4
MOLAR MASS:254.23 g/mol
APPEARNCE:white volatile solid
DENSITY:4.9 g/cm3
MELTING POINT:40.25 °C
BOILING POINT: 129.7 °C
INFORMATION OF OSMIC ACID:Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO4. The compound is noteworthy for its many uses, despite the rarity of osmium. It also has a number of interesting properties, one being that the solid is volatile. The compound is colourless, but most samples appear yellow.[5] This is most likely due to the presence of the impurity OsO2, which is yellow-brown in colour.
USES OF OSMIC ACID:n organic synthesis OsO4 is widely used to oxidise alkenes to the vicinal diols, adding two hydroxyl groups at the same side (syn addition). See reaction and mechanism above. This reaction has been made both catalytic (Upjohn dihydroxylation) and asymmetric (Sharpless asymmetric dihydroxylation).
Osmium(VIII) oxide is also used in catalytic amounts in the Sharpless oxyamination to give vicinal amino-alcohols.
In combination with sodium periodate, OsO4 is used for the oxidative cleavage of alkenes (Lemieux-Johnson oxidation) when the periodate serves both to cleave the diol formed by dihydroxylation, and to reoxidize the OsO3 back to OsO4. The net transformation is identical to that produced by ozonolysis. Below an example from the total synthesis of Isosteviol.
SAFTY:OsO4 is highly poisonous, even at low exposure levels, and must be handled with appropriate precautions. In particular, inhalation at concentrations well below those at which a smell can be perceived can lead to pulmonary edema and subsequent death. Noticeable symptoms can take hours to appear after exposure.
OsO4 also stains the human cornea, which can lead to blindness if proper safety precautions are not observed. The permissible exposure limit for osmium(VIII) oxide (8 hour time-weighted average) is 200 µg/m3.[7] Osmium(VIII) oxide can penetrate plastics and therefore is stored in glass under refrigeration.[14]
On April 6, 2004 British intelligence sources believed they had foiled a plot to detonate a bomb involving OsO4.[23] Experts interviewed by New Scientist affirmed osmium(VIII) oxide's toxicity, though some highlighted the difficulties of using it in a weapon: osmium(VIII) oxide is very expensive. The osmium(VIII) oxide may be destroyed by the blast; remaining toxic fumes may also be dispersed by the blast.