Chemical Properties
colorless, nonvolatile solid; can be obtained by reacting an ether solution of AlCl3 with LiH; used as a catalyst for organic polymerization processes [MER06]
Uses
As catalyst for polymerizations; reducing agent. Lithium aluminum hydride, q.v. is a more powerful reagent because of its greater soly.
General Description
A colorless to white solid.
Air & Water Reactions
Ignites in moist air. Ignites in air with or without oxygen enrichment [Bretherick 1979 p. 221]. Explosively hydrolyzed by water (forms hydrogen gas) [Ruff J.K. Inorg. Synth 1967, 9, 34].
Reactivity Profile
Aluminium hydride is a powerful reducing agent. May react violently with oxidizers. Prolonged exposure to heat may cause spontaneous decomposition. Can also decompose spontaneously at ambient temperature with explosive violence. Occasionally, explosions have occurred when Aluminium hydride was stored in ether. The explosions have been blamed on the presence of carbon dioxide impurity in the ether [J. Amer. Chem. Soc. 70:877 1948]. Can emit toxic fumes on contact with acid or fumes from an acid. [Lewis]. At elevated temperatures, the hydride reduces carbon dioxide or sodium hydrogen carbonate to methane and ethane. These gases are the explosive products formed when CO2 extinguishers have been used during hydride fires. The 1:1 complexes of the hydride (as a complex with ether or dimethylamine) and various tetrazole derivatives are explosive. Tetrazoles include, 2-methyl, 2-ethyl, 5-ethyl, 2-methyl-5-vinyl, 5-amino-2-ethyl, etc., [US Pat. 3 396 170, 1968].
Health Hazard
Inhalation or contact with vapors, substance or decomposition products may cause severe injury or death. May produce corrosive solutions on contact with water. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution.
Fire Hazard
Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard.
Physical properties
Colorless cubic crystal; very unstable; decomposes in water; ?Η°? ?11.0 kcal/mol (-46.0kJ/mol).
Definition
ChEBI: Alumane is an aluminium hydride and a mononuclear parent hydride.
Preparation
Aluminum hydride is prepared by the reaction of lithium hydride with aluminum chloride in diethyl ether.
3LiH + AlCl3 → AlH3 + 3LiCl
