Adverts

Open Access Articles- Top Results for Sodium azide

Sodium azide

Sodium azide
160px
260px
colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Names

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-


Other names
Sodium trinitride
Smite
Azium
colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Identifiers#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-



26628-22-8 7pxY
ChEBI CHEBI:278547 7pxY
ChEMBL ChEMBL89295 7pxY
ChemSpider 30958 7pxY
EC number 247-852-1
Jmol-3D images Image
PubChem Template:Chembox PubChem/format
RTECS number VY8050000
UN number 1687
colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Properties

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

NaN3
Molar mass 65.0099 g/mol
Appearance colorless to white solid
Odor odorless
Density 1.846 g/cm3 (20 °C)
Melting point Script error: No such module "convert". violent decomposition
38.9 g/100 mL (0 °C)
40.8 g/100 mL (20 °C)
55.3 g/100 mL (100 °C)
Solubility very soluble in ammonia
slightly soluble in benzene
insoluble in ether, acetone, hexane, chloroform
Solubility in methanol 2.48 g/100 mL (25 °C)
Solubility in ethanol 0.22 g/100 mL (0 °C)
Acidity (pKa) 4.8
colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Structure

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

Crystal structure Hexagonal, hR12[1]
Space group R-3m, No. 166
colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Thermochemistry

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

76.6 J/mol K
70.5 J/mol K
21.3 kJ/mol
99.4 kJ/mol
colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Hazards

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

SDS External MSDS
EU Index 011-004-00-7
EU classification Highly toxic (T+)
Very dangerous for the environment (N)
R-phrases R28, R32, R50/53
S-phrases (S1/2), S28, S45, S60, S61
NFPA 704

Error: Must specify an image in the first line.

1
4
3
Flash point Script error: No such module "convert".
27 mg/kg (oral, rats/mice)[1]
US health exposure limits (NIOSH):

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. style="padding-left:0.5em;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. none[2] #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. style="padding-left:0.5em;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. C 0.1 ppm (as HN3) [skin] C 0.3 mg/m3 (as NaN3) [skin][2] #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. style="padding-left:0.5em;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. N.D.[2] #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

colspan=2 style="background:#f8eaba; border-top:2px solid transparent; border-bottom:2px solid transparent; text-align:center;" #REDIRECTmw:Help:Magic words#Other
This page is a soft redirect. Related compounds

#REDIRECTmw:Help:Magic words#Other
This page is a soft redirect.-

Other anions
Sodium cyanide
Other cations
Potassium azide
Ammonium azide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 14pxN verify (what is10pxY/10pxN?)
Infobox references

Sodium azide is the inorganic compound with the formula NaN3. This colorless salt is the gas-forming component in many car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance, is highly soluble in water, and is very acutely toxic.

Structure

Sodium azide is an ionic solid. Two crystalline forms are known, rhombohedral and hexagonal.[1][4] Both adopt layered structures. The azide anion is very similar in each form, being centrosymmetric with N–N distances of 1.18 Å. The Template:Chem/atomTemplate:Chem/atom ion has octahedral. Each azide is linked to six Na+ centers, with three Na-N bonds to each terminal nitrogen center.[5]

Preparation

The common synthesis method is the "Wislicenus process," which proceeds in two steps from ammonia. In the first step, ammonia is converted to sodium amide:

2 Na + 2 NH3 → 2 NaNH2 + H2

The sodium amide is subsequently combined with nitrous oxide:

2 NaNH2 + N2O → NaN3 + NaOH + NH3

These reactions are the basis of the industrial route, which produces about 250 tons/y in 2004, with production increasing owing to the popularization of airbags.[6]

Laboratory methods

Curtius and Thiele developed another production process where a nitrite ester is converted to sodium azide using hydrazine. This method is suited for laboratory preparation of sodium azide:

2 NaNO2 + 2 C2H5OH +H2SO4 → 2 C2H5ONO + Na2SO4 + 2 H2O
C2H5ONO + N2H4-H2O + NaOH → NaN3 + C2H5OH + 3 H2O

Alternatively the salt can be obtained by the reaction of sodium nitrate with sodium amide.[7]

Applications

Automobile airbags and airplane escape chutes

Older airbag formulations contained mixtures of oxidizers and sodium azide and other agents including ignitors and accelerants. An electronic controller detonates this mixture during an automobile crash:

2 NaN3 → 2Na + 3 N2

The same reaction occurs upon heating the salt to approximately 300 °C. The sodium that is formed is a potential hazard alone and, in automobile airbags, it is converted by reaction with other ingredients, such as potassium nitrate and silica. In the latter case, innocuous sodium silicates are generated.[8] Sodium azide is also used in airplane escape chutes. Newer generation air bags contain nitroguanidine or similar less sensitive explosives.

Organic and inorganic synthesis

Due to its explosion hazard, sodium azide is of only limited value in industrial scale organic chemistry. In the laboratory, it is used in organic synthesis to introduce the azide functional group by displacement of halides. The azide functional group can thereafter be converted to an amine by reduction with either SnCl2 in ethanol or lithium aluminium hydride or a tertiary phosphine, such as triphenylphosphine in the Staudinger reaction, with Raney nickel or with hydrogen sulfide in pyridine.

Sodium azide is a versatile precursor to other inorganic azide compounds, e.g., lead azide and silver azide, which are used in explosives.

Biochemistry and biomedical uses

Sodium azide is a useful probe reagent, mutagen, and preservative. In hospitals and laboratories, it is a biocide; it is especially important in bulk reagents and stock solutions which may otherwise support bacterial growth where the sodium azide acts as a bacteriostatic by inhibiting cytochrome oxidase in gram-negative bacteria; gram-positive (streptococci, pneumococci, lactobacilli) are intrinsically resistant.[9] It is also used in agriculture for pest control.

Azide inhibits cytochrome oxidase by binding irreversibly to the heme cofactor in a process similar to the action of carbon monoxide. Sodium azide particularly affects organs that undergo high rates of respiration, such as the heart and the brain.[citation needed]

Reactions

Treatment of sodium azide with strong acids gives hydrazoic acid, which is also extremely toxic:

Template:Chem/atomTemplate:Chem/atom + Template:Chem/atomTemplate:Chem/atomTemplate:Chem/atomTemplate:Chem/atomTemplate:Chem/atom

Aqueous solutions contain minute amounts of hydrogen azide, as described by the following equilibrium:

Template:Chem/atomTemplate:Chem/atomTemplate:Chem/atom + Template:Chem/atomTemplate:Chem/atomTemplate:Chem/atom 15px Template:Chem/atomTemplate:Chem/atom + Template:Chem/atomTemplate:Chem/atom (K = 10Script error: No such module "Su".)

Sodium azide can be destroyed by treatment with nitrous acid solution:[10]

2 NaN3 + 2 HNO2 → 3 N2 + 2 NO + 2 NaOH

Safety considerations

Sodium azide is a severe poison. It may be fatal in contact with skin or if swallowed. Even minute amounts can cause symptoms. The toxicity of this compound is comparable to that of soluble alkali cyanides and the lethal dose for an adult human is about 0.7 grams.[11] No toxicity has been reported from spent airbags.[12]

References

  1. ^ a b c Stevens E. D., Hope H. (1977). "A Study of the Electron-Density Distribution in Sodium Azide, Template:Chem/atomTemplate:Chem/atom". Acta Crystallographica A 33 (5): 723–729. doi:10.1107/S0567739477001855. 
  2. ^ a b c "NIOSH Pocket Guide to Chemical Hazards #0560". National Institute for Occupational Safety and Health (NIOSH). 
  3. ^ http://www.lamission.edu/lifesciences/MSDS/MSDS/SodiumAzide.pdf
  4. ^ Wells, A. F. (1984), Structural Inorganic Chemistry (5th ed.), Oxford: Clarendon Press, ISBN 0-19-855370-6 
  5. ^ Pringle, G.E.; Noakes, D.E. "The Crystal Structures of Lithium, Sodium and Strontium Azides" Acta Crystallographica 1968, volume B24, p.262. doi:10.1107/S0567740868002062
  6. ^ Horst H. Jobelius, Hans-Dieter Scharff "Hydrazoic Acid and Azides" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a13_193
  7. ^ Holleman, A. F.; Wiberg, E. (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5 
  8. ^ Betterton, E. A. (2003). "Environmental Fate of Sodium Azide Derived from Automobile Airbags". Critical Reviews in Environmental Science and Technology 33 (4): 423–458. doi:10.1080/10643380390245002. 
  9. ^ Lichstein, H. C.; Soule, M. H. (1943). "Studies of the Effect of Sodium Azide on Microbic Growth and Respiration: I. The Action of Sodium Azide on Microbic Growth". Journal of Bacteriology 47 (3): 221–230. PMC 373901. PMID 16560767. 
  10. ^ Committee on Prudent Practices for Handling, Storage, and Disposal of Chemicals in Laboratories, Board on Chemical Sciences and Technology, Commission on Physical Sciences, Mathematics, and Applications, National Research Council (1995). "Disposal of Waste". Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. Washington, DC: National Academy Press. p. 165. ISBN 0-309-05229-7. 
  11. ^ "MSDS: sodium azide". Mallinckrodt Baker. 2008-11-21. MSDS S2906. 
  12. ^ Olson, K. R. (2007). Poisoning and Drug Overdose. McGraw-Hill Professional. p. 123. ISBN 0-07-144333-9. 

External links