Sodium aluminium hydride
Names | |
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IUPAC name
Sodium aluminium hydride
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Systematic IUPAC name
Sodium alumanuide | |
Other names
Sodium tetrahydroaluminate
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Identifiers | |
3D model (
JSmol ) |
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ECHA InfoCard
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100.033.986 |
EC Number |
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PubChem CID
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UN number | 2835 |
CompTox Dashboard (EPA)
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Properties | |
AlH4Na | |
Molar mass | 54.003 g·mol−1 |
Appearance | White or gray crystalline solid |
Density | 1.24 g/cm3 |
Melting point | 178 °C (352 °F; 451 K) |
Solubility | soluble in THF (16 g/100 mL at room temperature) |
Hazards | |
GHS labelling: | |
NFPA 704 (fire diamond) | |
Flash point | −22 °C; −7 °F; 251 K |
185 °C (365 °F; 458 K) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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740 mg/kg (oral, mouse) |
Safety data sheet (SDS) | Fisher Scientific |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium aluminium hydride or sodium alumanuide is an
Structure, preparation, and reactions
Sodium tetrahydroaluminate adopts the structure of (is isostructural with)
4 centers are linked with eight-coordinate Na+ cations.[1]
- Na + Al + 2 H2 → NaAlH4
As a suspension in diethyl ether, it reacts with lithium chloride to give the popular reagent lithium aluminium hydride:
- LiCl + NaAlH4 → LiAlH4 + NaCl
The compound reacts rapidly, even violently, with protic reagents, such as water, as described in this idealized equation:
- 4 H2O + NaAlH4 → "NaAl(OH)4" + 4 H2
Applications
Hydrogen storage
Sodium alanate
- 3 NaAlH4 → Na3AlH6+ 2 Al + 3 H2
- Na3AlH6 → 3 NaH + Al + 3/2 H2
Sodium tetrahydroaluminate can release up to 7.4 wt % of hydrogen when heated at 200 °C (392 °F). Absorption can be slow, with several minutes being required to fill a tank. Both release and uptake are catalysed by titanium.[5]
Reagent in organic chemistry
Sodium aluminium hydride is a strong
.Safety
Sodium aluminium hydride is highly flammable. It does not react in dry air at room temperature but is very sensitive to moisture. It ignites or explodes on contact with water.