Monosodium acetylide

{{Chembox

| ImageFile = Monosodium acetylide Structural Formula V1.svg

| ImageSize =

| ImageAlt =

| IUPACName = Ethynylsodium

| OtherNames = {{ubl|Sodium hydrogen acetylide|Sodium hydrogen ethynide}}

|Section1={{Chembox Identifiers

| CASNo = 1066-26-8

| CASNo_Ref = {{Cascite|correct|CAS}}

| ChEBI = 55387

| ChemSpiderID = 92108

| EC_number = 213-908-9

| Gmelin = 174471

| PubChem = 2733336

| StdInChI=1S/C2H.Na/c1-2;/h1H;/q-1;+1

| StdInChIKey = SFDZETWZUCDYMD-UHFFFAOYSA-N

| SMILES = C#[C-].[Na+]

}}

|Section2={{Chembox Properties

| Formula = {{chem2|NaC\tCH}}

| Na = 1|C=2|H=1

| MolarMass =

| Appearance = white solid

| Density = 1.352 g/cm³

| MeltingPt =

| MeltingPt_notes =

| BoilingPt =

| BoilingPt_notes =

| Solubility = hydrolysis}}

|Section3={{Chembox Hazards

| GHS_ref={{cite web |title=Sodium acetylide |url=https://pubchem.ncbi.nlm.nih.gov/compound/2733336#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |access-date=3 September 2023 |language=en}}

| GHSPictograms = {{GHS02}}{{GHS05}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|261|314}}

| PPhrases = {{P-phrases|231+232|260|264|280|301+330+331|302+361+354|304+340|305+354+338|316|321|363|370+378|402+404|405|501}}

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

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Monosodium acetylide, also known as sodium hydrogen acetylide, is an organosodium compound with the formula {{chem2|NaC\tCH}}. It is a sodium salt of acetylene, consisting of sodium cations {{chem2|Na+}} and hydrogen acetylide anions {{chem2|−C\tCH}}. It is a derived from acetylene by deprotonation using a sodium base, typically sodium amide.{{cite journal |doi=10.15227/orgsyn.030.0015 |title=n-Butylacetylene |journal=Organic Syntheses |date=1950 |volume=30 |page=15|author=K. N. Campbell, B. K. Campbell}}

:{{chem2|HC\tCH + NaNH2 → NaC\tCH + NH3}}

This compound, a white solid, has been characterized by neutron diffraction, which revealed an Na-C bond and a {{chem2|C\tC}} bond of 127 pm, which is longer than the {{chem2|C\tC}} bond length in acetylene itself (120.4 pm).{{cite journal |doi=10.1063/1.1676972 |title=Neutron Structure Determination of Monosodium Acetylide, NaC₂H, at 293 and 5K |date=1972 |last1=Atoji |first1=Masao |journal=The Journal of Chemical Physics |volume=56 |issue=10 |pages=4947–4951 |bibcode=1972JChPh..56.4947A}} As a reagent, monosodium acetylide has been largely displaced by monolithium acetylide, which can be prepared more easily.{{cite journal |doi=10.15227/orgsyn.068.0014 |title=Preparation and Use of Lithium Acetylide: 1-Methyl-2-Ethynyl-endo-3,3-Dimethyl-2-Norbornanol |journal=Organic Syntheses |date=1990 |volume=68 |page=14|author1=M. M. Midland|author2= J. I. McLoughlin|author3= R. T. Werley Jr.}}

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

:{{chem2|NaC\tCH + H2O → HC\tCH + NaOH}}

Monosodium acetylide is used in the Nef synthesis.