*** Welcome to piglix ***

Lithium aluminium hydride

Lithium aluminium hydride
Wireframe model of lithium aluminium hydride
Unit cell ball and stick model of lithium aluminium hydride
100 grams of lithium aluminium hydride
Names
Preferred IUPAC name
Lithium tetrahydridoaluminate(III)
Systematic IUPAC name
Lithium alumanuide
Other names
Lithium aluminium hydride

Lithal
Lithium alanate
Lithium aluminohydride
Lithium tetrahydridoaluminate

Lithium tetrahydridoaluminate(III)
Identifiers
3D model (Jmol)
Abbreviations LAH
ChEBI
ChemSpider
ECHA InfoCard 100.037.146
EC Number 240-877-9
13167
PubChem CID
RTECS number BD0100000
Properties
LiAlH4
Molar mass 37.95 g/mol
Appearance white crystals (pure samples)
grey powder (commercial material)
hygroscopic
Odor odorless
Density 0.917 g/cm3, solid
Melting point 150 °C (302 °F; 423 K) (decomposes)
Reacts
Solubility in tetrahydrofuran 112.332 g L−1
Solubility in diethyl ether 39.5 g/100 mL
Structure
monoclinic
P21/c
Thermochemistry
86.4 J/mol K
87.9 J/mol K
-117 kJ/mol
-48.4 kJ/mol
Hazards
Main hazards Extremely Flammable F+
Safety data sheet External MSDS
GHS pictograms Water-react. 1
GHS signal word DANGER
H260
R/S statement R15, S7/8, S24/25, S43
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g., diesel fuel Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazard W: Reacts with water in an unusual or dangerous manner. E.g., cesium, sodiumNFPA 704 four-colored diamond
Flash point 125 °C (257 °F; 398 K)
Related compounds
Related hydride
aluminium hydride
sodium borohydride
sodium hydride
Sodium aluminium hydride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Lithal
Lithium alanate
Lithium aluminohydride
Lithium tetrahydridoaluminate

Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage.

LAH is a colorless solid, but commercial samples are usually gray due to contamination. This material can be purified by recrystallization from diethyl ether. Large-scale purifications employ a Soxhlet extractor. Commonly, the impure gray material is used in synthesis, since the impurities are innocuous and can be easily separated from the organic products. The pure powdered material is pyrophoric, but not its large crystals. Some commercial materials contain mineral oil to inhibit reactions with atmospheric moisture, but more commonly it is packed in moisture-proof plastic sacks.

LAH violently reacts with water, including atmospheric moisture. The reaction proceeds according to the following idealized equation:

This reaction provides a useful method to generate hydrogen in the laboratory. Aged, air-exposed samples often appear white because they have absorbed enough moisture to generate a mixture of the white compounds lithium hydroxide and aluminium hydroxide.


...
Wikipedia

...