Monosodium acetylide

Monosodium acetylide, also known as sodium hydrogen acetylide, is an organosodium compound with the formula NaC≡CH. It is a sodium salt of acetylene, consisting of sodium cations (Na⁺) and hydrogen acetylide anions (⁻C≡CH).^{[contradictory]} It is a derived from acetylene by deprotonation using a sodium base, typically sodium amide.^[2]

HC≡CH + NaNH₂ → NaC≡CH + NH₃

Monosodium acetylide

Names
IUPAC name Ethynylsodium
Other names Sodium hydrogen acetylide Sodium hydrogen ethynide
Identifiers
CAS Number	1066-26-8 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:55387
ChemSpider	92108
ECHA InfoCard	100.012.645
EC Number	213-908-9
Gmelin Reference	174471
PubChem CID	2733336
CompTox Dashboard (EPA)	DTXSID50910044
InChI InChI=1S/C2H.Na/c1-2;/h1H;/q-1;+1 Key: SFDZETWZUCDYMD-UHFFFAOYSA-N
SMILES C#[C-].[Na+]
Properties
Chemical formula	C2HNa
Molar mass	48.020 g·mol−1
Appearance	white solid
Density	1.352 g/cm3
Solubility in water	hydrolyzes
Hazards
GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H261, H314
Precautionary statements	P231+P232, P260, P264, P280, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P363, P370+P378, P402+P404, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

This compound, a white solid, has been characterized by neutron diffraction, which revealed an Na-C bond^{[clarification needed]} and a C≡C bond of 127 pm, which is longer than the C≡C bond length in acetylene itself (120.4 pm).^[3]

Monosodium acetylide can be used as a strong nucleophile in organic synthesis.^[2] However, it has largely been displaced in this application by monolithium acetylide, which can be prepared more easily.^[4]

Monosodium acetylide hydrolizes in contact with water, producing sodium hydroxide and acetylene.

NaC≡CH + H₂O → HC≡CH + NaOH

Monosodium acetylide is used in the Nef synthesis.