Lithium azide

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Lithium azide
Names
IUPAC name
Lithium azide
Other names
Lithium triazide
Properties
LiN3
Molar mass 48.96 g/mol
Appearance Colorless solid
Odor Odorless
Melting point 115 °C (239 °F; 388 K) (decomposes)
Boiling point 298 °C (568 °F; 571 K) (explodes)
36.12 g/100 ml (10 °C)
62.07 g/100 ml (15.5 °C)
66.41 g/100 ml (16 °C)[1]
Solubility Reacts with acids
Soluble in ethanol, hydrazine, methanol
Insoluble in diethyl ether
Solubility in ethanol 20.26 g/100 ml (16 °C)
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Sigma-Aldrich (20% aq. solution)
Related compounds
Related compounds
Sodium azide
Potassium azide
Rubidium azide
Caesium azide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Lithium azide is the lithium salt of hydrazoic acid, with the chemical formula LiN3.

Properties

Chemical

Lithium azide decomposes when heated.

Physical

Lithium azide is a colorless crystalline solid, soluble in water. The compound can be encountered as a monohydrate between -31 °C and 68 °C, and above this temperature, the compound exists only as anhydrous.[2]

Explosive

Lithium azide has been characterized as being explosive. If heated rapidly above 115 °C it will violently decompose, but its decomposition can be delayed until 298 °C if heated slowly.[3] It has a reported detonation velocity of 990 m/s.

Availability

Lithium azide is sold by chemical suppliers, albeit only as solution.

Due to the high toxicity of azides, it is not generally available for the public.

Preparation

It can be prepared by metathesis reaction between sodium azide and lithium nitrate or lithium sulfate solutions:[4]

NaN3 + LiNO3 → LiN3 + NaNO3
2 NaN3 + Li2SO4 → 2 LiN3 + Na2SO4

It can also be prepared by reacting lithium sulfate with barium azide. Barium sulfate precipitates out of the solution and after filtering, the solution is slowly evaporated to obtain the pure lithium azide.

Ba(N3)2 + Li2SO4 → 2 LiN3 + BaSO4

Very pure lithium azide can be obtained by neutralizing lithium carbonate with hydrazoic acid.

Projects

  • Azidation agent
  • Make other azide salts

Handling

Safety

Lithium azide is extremely toxic. The toxicity of azides is similar that of cyanides. There is no known antidote.

Storage

Lithium azide should be stored in spark-free containers, away from moisture or any acidic vapors.

Disposal

When disposed of, it must never be poured down the drain, as it will react to either copper or lead plumbing to yield copper azide, which is highly sensitive. Hydrolysis can also occur in aqueous solutions, at certain pH. Lithium azide must be treated with nitrous acid before being discarded. This can be easily obtained by acidifying sodium nitrite.

References

  1. https://aip.scitation.org/doi/10.1063/1.1563591
  2. A. P. Rollet, J. Wohlgemuth, Compt. Rend., 198, 1772 (1934)
  3. Fair H.D, Walker R.F. (ed.) - Energetic Materials. Physics and Chemistry of Inorganic Azides. 1-Plenum Press (1977)
  4. http://www.lambdasyn.org/synfiles/lithiumazid.htm

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