Sodium oxide

Sodium oxide

Discussion
Ask a question about 'Sodium oxide'
Start a new discussion about 'Sodium oxide'
Answer questions from other users
Full Discussion Forum
 
Encyclopedia
Sodium oxide is a chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula Na
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

2O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

. It is used in ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

s and glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

es, though not in a raw form. Treatment with water affords sodium hydroxide.
Na2O + H2O → 2 NaOH


The alkali metal oxides M2O (M = Li, Na, K, Rb) crystallise in the antifluorite structure. In this motif the positions of the anions and cations are reversed relative to their positions in CaF2
Calcium fluoride
Calcium fluoride is the inorganic compound with the formula CaF2. This ionic compound of calcium and fluorine occurs naturally as the mineral fluorite . It is the source of most of the world's fluorine. This insoluble solid adopts a cubic structure wherein calcium is coordinated to eight fluoride...

, with sodium ions tetrahedrally coordinated to 4 oxide ions and oxide cubically coordinated to 8 sodium ions.

Preparation


Sodium oxide is produced by the reaction of sodium with sodium hydroxide, sodium peroxide
Sodium peroxide
Sodium peroxide is the inorganic compound with the formula Na2O2. This solid is the product when sodium is burned with oxygen. It is a strong base and a potent oxidizing agent. It exists in several hydrates and peroxyhydrates including Na2O2·2H2O2·4H2O, Na2O2·2H2O, Na2O2·2H2O2, and...

, or sodium nitrite
Sodium nitrite
Sodium nitrite is the inorganic compound with the chemical formula NaNO2. It is a white to slight yellowish crystalline powder that is very soluble in water and is hygroscopic...

:
2 NaOH + 2 Na → 2 Na2O + H2
Na2O2 + 2 Na → 2 Na2O
2 NaNO2 + 6 Na → 4 Na2O + N2


Most of these reactions rely on the reduction of something by sodium, whether it is hydroxide, peroxide, or nitrite.

Burning sodium in air will produce Na2O and about 20% sodium peroxide
Sodium peroxide
Sodium peroxide is the inorganic compound with the formula Na2O2. This solid is the product when sodium is burned with oxygen. It is a strong base and a potent oxidizing agent. It exists in several hydrates and peroxyhydrates including Na2O2·2H2O2·4H2O, Na2O2·2H2O, Na2O2·2H2O2, and...

 Na2O2.
6 Na + 2 O2 → 2 Na2O + Na2O2

Glass making


Sodium oxide is a significant component of glasses and windows although it is added in the form of "soda" (sodium carbonate). Sodium oxide does not explicitly exist in glasses, since glasses are complex cross-linked polymers. Typically, manufactured glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

 contains around 15% sodium oxide, 70% silica (silicon dioxide
Silicon dioxide
The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...

) and 9% lime (calcium oxide
Calcium oxide
Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....

). The sodium carbonate "soda" serves as a flux to lower the temperature at which the silica melts. Soda glass has a much lower melting temperature than pure silica, and has slightly higher elasticity. These changes arise because the silicon dioxide and soda react to form sodium silicates of the general formula Na2[SiO2]x[SiO3].
Na2CO3 → Na2O + CO2

Na2O + SiO2 → Na2SiO3

External links