Aluminium hydride Property

Melting point:

decomposes at 160℃ [HAW93]

Density 

1.45

solubility 

reacts with H2O

form 

colorless hexagonal crystals

color 

colorless hexagonal, hexane crystals, crystalline

Water Solubility 

evolves H2 in H2O [HAW93]

CAS DataBase Reference

7784-21-6

EPA Substance Registry System

Aluminum trihydride (7784-21-6)

Safety

RIDADR 

2463

HazardClass 

4.3

PackingGroup 

I

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H260In contact with water releases flammable gases which may ignite spontaneously

H314Causes severe skin burns and eye damage

Precautionary statements

P223Keep away from any possible contact with water, because of violent reaction and possible flash fire.

P231+P232Handle under inert gas. Protect from moisture.

P260Do not breathe dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P301+P330+P331IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.

P303+P361+P353IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.

P304+P340IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P310Immediately call a POISON CENTER or doctor/physician.

P321Specific treatment (see … on this label).

P335+P334Brush off loose particles from skin. Immerse in cool water/wrap in wet bandages.

P363Wash contaminated clothing before reuse.

P370+P378In case of fire: Use … for extinction.

P402+P404Store in a dry place. Store in a closed container.

P405Store locked up.

P501Dispose of contents/container to..…

Aluminium hydride Chemical Properties,Usage,Production

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]

Physical properties

Colorless cubic crystal; very unstable; decomposes in water; ?Η°? ?11.0 kcal/mol (-46.0kJ/mol).

Uses

Aluminum Hydride is a relatively unstable polymeric covalent hydride that received considerable attention in the mid- 1960s because of its potential as a high energy additive to solid rocket propellants. The projected uses, including aluminum plating, never materialized, and in spite of intense research and development, commercial manufacture has not been undertaken. The synthetic methods developed were costly.

Uses

As catalyst for polymerizations; reducing agent. Lithium aluminum hydride, q.v. is a more powerful reagent because of its greater soly.

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

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.

Safety Profile

Hydrides of some metals (such as ASH3 are extremely toxic. Dangerous fire hazard. An unstable material which is spontaneously flammable in air or O2. Evolves explosive H2 upon contact with moisture. Severe explosion hazard by chemical reaction wherein H2 gas is produced, also in contact with methyl ethers contaminated by Con. Mixtures with tetrazole derivatives are explosive. Reacts with oxidzing materials. On contact with acid or acid fumes, it can emit toxic fumes. See also HYDRIDES and ALUMINUM COMPOUNDS.