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Key Documents

O5500

Sigma-Aldrich

Osmium tetroxide

Sealed ampule.

Synonym(s):

Osmium(VIII)-oxide, ‘Osmic acid’

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About This Item

Linear Formula:
OsO4
CAS Number:
Molecular Weight:
254.23
EC Number:
MDL number:
UNSPSC Code:
12171500
PubChem Substance ID:
NACRES:
NA.47

vapor density

8.8 (vs air)

Quality Level

vapor pressure

7 mmHg ( 20 °C)

form

powder

reaction suitability

reagent type: oxidant

bp

130 °C (lit.)

mp

39.5-41 °C (lit.)

SMILES string

O=[Os](=O)(=O)=O

InChI

1S/4O.Os

InChI key

VUVGYHUDAICLFK-UHFFFAOYSA-N

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General description

Osmium tetroxide (OsO4) is a heavy tetrahedral, symmetrical molecule composed of osmium, a third-row transition metal. Osmium tetroxide is both a dye, and a non-coagulant fixative agent in electron microscopy primarily used for the examination of biological tissue components in the histopathology laboratory. Specimens are postfixed with osmium testroxide to ensure preservation of the lipids.

Application

Osmium tetroxide has been used as a fixative reagent for Brevibacterium mcbrellneri, and curcumin treated human lung cancer cell lines′ observation with a scanning electron microscope. It is also suitable as a fixative for ultrastructural analysis of Toxoplasma gondii′s skeletal muscle cells.

Biochem/physiol Actions

Osmium tetroxide chemically combines with lipids making them insoluble; only 7% of the lipids can be extracted after the fixation. Therefore, the cell membranes comprising phospholipids become black and electron-dense after fixation in osmium tetroxide. It is also used to fix small amount of fat maintained in sections during paraffin processing.

Other Notes

Due to the hazardous nature of osmium tetroxide, it is recommended to use an ampule opener when using this chemical.

Pictograms

Skull and crossbonesCorrosion

Signal Word

Danger

Hazard Statements

Hazard Classifications

Acute Tox. 1 Dermal - Acute Tox. 2 Inhalation - Acute Tox. 2 Oral - Eye Dam. 1 - Skin Corr. 1B

Storage Class Code

6.1A - Combustible acute toxic Cat. 1 and 2 / very toxic hazardous materials

WGK

WGK 1

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificates of Analysis (COA)

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