osmium tetroxide

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os·mic ac·id

(oz'mik as'id),
OsO4; a volatile caustic and strong oxidizing agent; colorless crystals, poorly soluble in water, but soluble in organic solvents; the aqueous solution is a fat and myelin stain and a general fixative for electron microscopy.
Synonym(s): osmium tetroxide

osmium tetroxide

A volatile poisonous pale yellow solid, OsO4, with a pungent smell, used as an oxidizing agent and in solution to stain and fix biological material, especially lipids. Also called osmic acid.

osmium tetroxide


osmic acid

a substance used in the fixing of cytological preparations that is characterized by the small amount of distortion it causes.


a chemical element, atomic number 76, atomic weight 190.2, symbol Os. See Table 6.

osmium tetroxide
a pathology stain and fixative; called also osmic acid.
References in periodicals archive ?
Contrast can be tailored to a heterogeneous system with osmium tetroxide staining techniques where the reactivity of a stain is preferential towards the phase or component containing residual double bonds.
In the blends containing block copolymer, the location of the block cannot be distinguished from the PB homopolymer, because in both cases the PB was stained dark using osmium tetroxide.
Police crushed the "dirty bomb" scheme before the suspects managed to get hold of any osmium tetroxide.
OSMIUM tetroxide, OsO4, is used for testing chemicals worldwide.
5% glutaraldehyde and 1% osmium tetroxide, stained with 4% uranyl acetate, dehydrated through a graded series of alcohols and propylene oxide, and embedded in a mixture of Epon-substitute and Araldite.
5 hours in 1% osmium tetroxide, then stained en bloc for 1 hour in 5% aqueous uranyl acetate.
Osmium tetroxide came from Analytical Standards AB (Molnlycke, Sweden) and uranyl acetate and lead citrate from Merck (Darmstadt, Germany).
For ultrastructural studies, formalin-fixed tumor samples were washed, postfixed in buffered osmium tetroxide, dehydrated, and embedded in epoxy resin.
2) at room temperature (RT), post-fixed with 1% (w/v) osmium tetroxide in 100 mM sodium cacodylate, and dehydrated with an ethanol series.
Fresh tissue samples were also fixed in glutaraldehyde, postfixed in osmium tetroxide, and Epon embedded for electron microscopy.
For electron microscopy, tumor tissue was fixed in 3% glutaraldehyde, postfixed in 1% osmium tetroxide, and embedded in Epon; thin sections were stained with lead citrate.