sodium hydride Identifiers Properties Hazards
CAS number 7646-69-7
molecule formula NaH
Molar mass 23.99 g/mol
Appearance colorless to gray solid
Density 1.396 g/cm³, solid
melting point

800 °C with decomp.

Solubility in water Reacts
MSDS exterior MSDS
EU classification Flammable (F)
NFPA 704
R-phrases R15 S-phrases (S2), S7/8, S24/25, S42 associated Compounds various other cations Potassium hydride related compounds salt borohydride other than where listed otherwise, data are provided for products in their typical state(at 25°C, 100kPa)Infobox disclaimer and references

Sodium hydride is the chemical compound with the formula NaH. That is mostly used together a strong base in necessary synthesis. NaH is representative of the saline hydrides, definition it is a salt-like hydride, written of Na+ and H− ions, in comparison to the an ext molecular hydrides such as borane, methane, ammonia and water. That is an ionic material that is insoluble in organic solvents (although apparently soluble in molten Na), regular with the truth that H− stays an unknown anion in solution. Since of the insolubility that NaH, every reactions including NaH occur at the surface ar of the solid.


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an easy properties and structure

NaH is produced by the straight reaction that hydrogen and also liquid sodium.

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<1> Pure NaH is colorless, back samples generally show up gray. NaH is ca. 40% much more dense 보다 Na (0.968 g/cm³).

NaH, like LiH, KH, RbH, and also CsH, adopts the NaCl crystal structure. In this motif, each Na+ ion is surrounding by six H− centers in one octahedral geometry. The ionic radii the H− (146 afternoon in NaH) and also F− (133 pm) space comparable, as judged through the Na−H and also Na−F distances.<2>

Applications in essential synthesis

First and also foremost, NaH is a basic of wide scope and also utility in necessary chemistry.<3> the is capable of deprotonating a wide selection of even weak Brønsted acids to provide the equivalent sodium derivatives. Usual "easy" substrates save on computer O-H, N-H, S-H bonds, including alcohols, phenols, pyrazoles, and thiols.

NaH many notably is employed come deprotonate carbon acids such as 1,3-dicarbonyls and also analogues such as malonic esters. The resulting sodium derivatives deserve to be alkylated. NaH is widely used to promote condensation reactions of carbonyl compounds via the Dieckmann condensation, Stobbe condensation, Darzens condensation, and Claisen condensation. Various other carbon acids prone to deprotonation through NaH incorporate sulfonium salts and DMSO.

In one illustrative reaction, NaH is offered to do sulfur ylides, which in turn are offered to convert ketones right into epoxides.Also, it is offered in one synthetic of the dithioimidodiphosphinates which space an interesting class of acac like ligands in inorganic chemistry.

NaH reduces Si-Si and also S-S bond in disilanes and disulfides. Otherwise, NaH hardly ever exhibits the reducing attributes of Na itself.

useful considerations

Sodium hydride is offered by many chemical companies such together Sigma-Aldrich and ACROS, usually as a mixture the 60% salt hydride (w/w) in mineral oil. Such a dispersion is more secure to handle and weigh 보다 pure NaH. The pure white hard is all set by rinsing the oil v pentane or THF, treatment being taken that the washings will contain traces of NaH that deserve to ignite in air. Reactions including NaH require an inert atmosphere, such together nitrogen gas. Typically NaH is provided as a suspension in THF; THF resists deprotonation but solvates plenty of organo sodium compounds.

Safety

NaH have the right to ignite in air, especially upon call with water. The reaction provides off hydrogen, probably explosively. Hydrolysis converts NaH into sodium hydroxide (NaOH), a caustic base.

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References


This post is licensed under the GNU complimentary Documentation License. That uses material from the Wikipedia post "Sodium_hydride". A list of writer is accessible in Wikipedia.