Sodium oxide
| Names | |
|---|---|
| IUPAC name
Sodium oxide
| |
| Other names
Disodium monoxide
Disodium oxide | |
| Properties | |
| Na2O | |
| Molar mass | 61.98 g/mol |
| Appearance | White solid |
| Odor | Odorless |
| Density | 2.27 g/cm3 |
| Melting point | 1,132 °C (2,070 °F; 1,405 K) |
| Boiling point | 1,950 °C (3,540 °F; 2,220 K) |
| Reacts | |
| Solubility | Reacts with alcohols, carboxylic acids, esters, halogens, mineral acids Insoluble in ethers, hydrocarbons |
| Vapor pressure | ~0 mmHg |
| Thermochemistry | |
| Std molar
entropy (S |
73 J·mol-1·K-1 |
| Std enthalpy of
formation (ΔfH |
-416 kJ/mol |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | Nn-flammable |
| Related compounds | |
| Related compounds
|
Sodium peroxide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Sodium oxide is a chemical compound with the formula Na2O. It is one of the three oxides of sodium, the other being sodium peroxide and sodium superoxide.
Contents
Properties
Chemical
Sodium oxide reacts with water to give sodium hydroxide. The reaction is highly exothermic.
- Na2O + H2O → 2 NaOH
Reaction with alcohols gives their corresponding alkoxides.
Physical
Sodium oxide is a white solid, which reacts with water and atmospheric moisture. It melts at 1,132 °C and boils at 1,950 °C, though it begins to sublime at 1275 °C.
Availability
Sodium oxide is sold by chemical suppliers, though it's difficult to get hold of.
Preparation
Sodium oxide can be prepared via several routes.
The most common method involves burning sodium in air. The reaction produces both sodium oxide and sodium peroxide, with the latter being around 20% of the product.
The reaction of metallic sodium with sodium hydroxide, sodium peroxide or sodium nitrite will also give sodium oxide.
Another common route involves the calcination of sodium carbonate at 800-1000 °C.
- Na2CO3 → Na2O + CO2
This reaction requires constant high temperature and takes place over a long time period.
A lower temperature route involves the decomposition of sodium ascorbate, which can be easily obtained by reacting sodium bicarbonate with ascorbic acid. The decomposition begins at 218 °C, yielding sodium oxide and furanes.[1]
Decomposition of sodium nitrite will give off nitrogen oxides and leave behind sodium oxide. Decomposition begins at around 320 °C.
The last three reactions give hot sodium oxide which can rapidly absorb moisture and carbon dioxide and convert back to sodium hydroxide/carbonate. Cooling of the hot sodium hydroxide should be done in an inert medium.
Projects
- Make pure sodium hydroxide
- Dry CO2 scrubber
- Make soda glass
Handling
Safety
Sodium oxide is extremely corrosive and reaction with water is highly exothermic.
Storage
Should be stored in air-tight containers. Schlenk flasks, gloveboxes, sealed ampoules are recommended.
Disposal
Sodium oxide should be neutralized by slow addition in cold acidified water. Aqueous phosphoric acid can be used as it has low volatility.
References
- ↑ Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 310
