Sodium amide

Sodium amide
Ball and stick, unit cell model of sodium amide
Ball and stick, unit cell model of sodium amide
Names
IUPAC name
  • Sodium amide
  • Sodium azanide
Other names
Sodamide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.064 Edit this at Wikidata
EC Number
  • 231-971-0
UNII
UN number 1390
  • InChI=1S/H2N.Na/h1H2;/q-1;+1 X markN
    Key: ODZPKZBBUMBTMG-UHFFFAOYSA-N X markN
  • [Na]N
  • [NH2-].[Na+]
Properties
NaNH2
Molar mass 39.013 g·mol−1
Appearance Colourless crystals
Odor Ammonia-like
Density 1.39 g/cm3
Melting point 210 °C (410 °F; 483 K)
Boiling point 400 °C (752 °F; 673 K)
Reacts
Solubility in liquid ammonia 40 mg/L
Acidity (pKa) 38 (conjugate acid)
Structure[citation needed]
orthorhombic
Thermochemistry[citation needed]
66.15 J/(mol·K)
76.9 J/(mol·K)
−118.8 kJ/mol
−59 kJ/mol
Hazards
GHS labelling:
GHS02: FlammableGHS05: Corrosive
Danger
H261, H314, H412
P223, P231+P232, P260, P264, P273, P280, P301+P330+P331, P303+P361+P353, P304+P340+P310, P305+P351+P338+P310, P335+P334, P363, P370+P378, P402+P404, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
3
3
2
W
450 °C (842 °F; 723 K)
Related compounds
Other anions
 Sodium bis(trimethylsilyl)amide
Other cations
Related compounds
 Ammonia
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula NaNH2. It is a salt composed of the sodium cation and the azanide anion. It is a white solid which is dangerously reactive toward water, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent.[citation needed] NaNH2 conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. NaNH2 has been widely employed as a strong base in organic synthesis.

Preparation and structure

Sodium amide can be prepared by the reaction of sodium with ammonia gas, but it is usually prepared by the reaction in liquid ammonia using iron(III) nitrate as a catalyst. The reaction is fastest at the boiling point of the ammonia (−33 °C (−27 °F; 240 K)). An electride, [Na(NH3)6]+e−, is formed as a reaction intermediate.

2 Na + 2 NH3 → 2 NaNH2 + H2

NaNH2 is a salt-like material and as such, crystallizes as an infinite polymer. The geometry about sodium is tetrahedral. In ammonia, NaNH2 forms conductive solutions, consistent with the presence of [Na(NH3)6]+ and NH−2 ions.

Uses

Sodium amide is mainly used as a strong base in organic chemistry, often suspended (it is insoluble) in liquid ammonia solution. One of the main advantages to the use of sodium amide is its relatively low nucleophilicity. In the industrial production of indigo, sodium amide is a component of the highly basic mixture that induces cyclisation of N-phenylglycine. The reaction produces ammonia, which is typically recycled.

Pfleger's synthesis of indigo dye.

Dehydrohalogenation

Sodium amide is a standard base for dehydrohalogenations. It induces the loss of two equivalents of hydrogen bromide from a vicinal dibromoalkane to give a carbon–carbon triple bond, as in a preparation of phenylacetylene. Usually two equivalents of sodium amide yields the desired alkyne. Three equivalents are necessary in the preparation of a terminal alkynes because the terminal CH of the resulting alkyne protonates an equivalent amount of base.

Hydrogen chloride and ethanol can also be eliminated in this way, as in the preparation of 1-ethoxy-1-butyne.

Cyclization reactions

Where there is no β-hydrogen to be eliminated, cyclic compounds may be formed, as in the preparation of methylenecyclopropane below.

Cyclopropenes, aziridines and cyclobutanes may be formed in a similar manner.

Deprotonation of carbon and nitrogen acids

Carbon acids which can be deprotonated by sodium amide in liquid ammonia include:

Acetylacetone loses two protons to form a dianion. Sodium amide will also deprotonate indole and piperidine.

It is however poorly soluble in solvents other than ammonia. Its use has been superseded by the related reagents sodium hydride, sodium bis(trimethylsilyl)amide (NaHMDS), and lithium diisopropylamide (LDA).

Other reactions

Safety

Sodium amide is a common reagent with a long history of laboratory use. It reacts violently on contact with water, producing ammonia and sodium hydroxide:

NaNH2 + H2O → NH3 + NaOH

When burned in oxygen, it will give oxides of sodium (which react with the produced water, giving sodium hydroxide) along with nitrogen oxides:

4 NaNH2 + 5 O2 → 4 NaOH + 4 NO + 2 H2O
4 NaNH2 + 7 O2 → 4 NaOH + 4 NO2 + 2 H2O

In the presence of limited quantities of air and moisture, such as in a poorly closed container, explosive mixtures of peroxides may form. This is accompanied by a yellowing or browning of the solid. As such, sodium amide is to be stored in a tightly closed container, under an atmosphere of an inert gas. Sodium amide samples which are yellow or brown in color represent explosion risks.

References

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  2. 1 2 Sigma-Aldrich Co., Sodium amide. Retrieved on 20 March 2026.
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  4. 1 2 "SDS - Sodium amide" (pdf). www.fishersci.com. ThermoFisher Scientific. 19 December 2025. pp. 3–5. Retrieved 20 March 2026.
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