Sodium hydride
| Names | |
|---|---|
| IUPAC name
Sodium hydride
| |
| Other names
Sodium monohydride
| |
| Properties | |
| NaH | |
| Molar mass | 23.99771 g/mol |
| Appearance | White or gray solid |
| Odor | Odorless |
| Density | 1.396 g/cm3 |
| Melting point | 300 °C (572 °F; 573 K) |
| Boiling point | 300–500 °C (572–932 °F; 573–773 K) Decomposes |
| Reacts | |
| Solubility | Reacts with alcohols, aldehydes, carboxylic acids, halocarbons, ketones Soluble in NaK, molten NaOH Insoluble in most solvents |
| Vapor pressure | ~0 mmHg |
| Thermochemistry | |
| Std enthalpy of
formation (ΔfH |
-56.366 kJ/mol |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Related compounds | |
| Related compounds
|
Lithium hydride Calcium hydride |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Sodium hydride is the chemical compound with the chemical formula NaH. It is a strong base.
Contents
Properties
Chemical
Sodium hydride will react with water to release hydrogen.
Reaction with aluminium metal and hydrogen will give sodium aluminium hydride.
Physical
Sodium hydride is a white solid, which reacts with water.
Availability
It is sold by chemical suppliers, usually kept under mineral oil.
Preparation
Sodium hydride can be prepared by passing dry and air-free hydrogen over molten sodium metal, at 700-750 °C. The molten sodium sits in a steel crucible or boat, inside a quartz or refractory glass tube. Adding small amounts of calcium metal will accelerate the process.[1] At room temperature, sodium reacts very slow with hydrogen to form sodium hydride.
Heating sodium metal and hydrogen in THF at 250-350 °C, at a pressure rising from 7 to 35 atm will give sodium hydride with a yield of 98%.[2]
Thermal decomposition of sodium aluminium hydride above 250 °C will give hydrogen, aluminium and sodium hydride.
- NaAlH4 → NaH + Al + 2 H2
Heating the powdered sodium carbide in an autoclave in the presence of hydrogen at 500 atm and 650°C will give sodium hydride. Yield of this process is 86%.[3]
Thermal decomposition of sodium amide, in a hydrogen atmosphere at 300 °C will give sodium hydride.[4]
Reduction of sodium hydroxide with a mixture of H2-N2 at 750 °C will give sodium hydride. Iron or manganese is used as catalyst.[5]
Hydrogenation of sodium azide at 120 °C in gaseous phase, without a solvent gives sodium hydride and ammonia.[6][7]
Sodium hydride is also produced, along with sodium carbide by reacting molten sodium metal with methane, at 300-500 °C.[8] Reaction of molten sodium metal with acetylene at 100-550 °C is another route.[9]
Projects
- Desiccant
- Reducing agent
- Make sodium aluminium hydride
Handling
Safety
Sodium hydride is water and air sensitive and must be handled with care and proper protection.
Storage
Sodium hydride must be kept in an air-tight container under inert atmosphere or inert solvent, like mineral oil.
Disposal
Adding it in a large volume of base, water or alcohol will suffice.
References
- ↑ Ephraim; Michel, E.; Helvetica Chimica Acta; vol. 4; (1921); p. 765
- ↑ http://www.google.com/patents/US2898195
- ↑ Patent; Goerrig, D.; Farbenfabriken Bayer A.-G.; DE953523; (1956); C. A.; (1959); p. 7526
- ↑ Guntz; Benoit; Bulletin de la Societe Chimique de France; vol. 41; (1927); p. 434 - 434
- ↑ Villard, P.; Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences; vol. 193; (1931); p. 681 - 685
- ↑ Wattenberg, H.; Ber. Dtsch. Chem. Ges.; vol. 63; (1930); p. 1667 - 1672
- ↑ Patent; Tiede, E.; DE417508; (1925)
- ↑ Kovalev; Journal of applied chemistry of the USSR; vol. 57; nb. 7 pt 1; (1984); p. 1368 - 1371
- ↑ Walker; Journal of Physical Chemistry; vol. 31; (1927); p. 982 - 982
Relevant Sciencemadness threads
- Articles containing unverified chemical infoboxes
- Chembox articles without image
- Chemical compounds
- Inorganic compounds
- Sodium compounds
- Hydrogen compounds
- Metal hydrides
- Bases
- Insoluble compounds
- Reducing agents
- Desiccants
- Materials unstable in acidic solution
- Materials that react with water
- Irritants
- Air-sensitive materials
- Pyrophoric materials
