Na2O

Sodium oxide, with the chemical formula Na2O, is an inorganic oxide of sodium. It is a white, highly hygroscopic solid that readily reacts with water to form sodium hydroxide and can absorb carbon dioxide from the air to form sodium carbonate.

Chemical properties and structure

Na2O is a basic oxide. It reacts vigorously with water: Na2O + H2O → 2 NaOH. It also reacts with acids to give corresponding sodium salts. In air it slowly hydrates and carbonates, reflecting its strong affinity for moisture and CO2. The solid adopts an antifluorite-type lattice, in which oxide ions form a lattice and sodium ions occupy tetrahedral sites.

Preparation

Industrial and laboratory routes include thermal decomposition of sodium hydroxide: 2 NaOH → Na2O + H2O. Another common preparation is the calcination of sodium carbonate with calcium oxide: Na2CO3 + CaO → Na2O + CaCO3. Both routes emphasize the high-temperature removal of water or carbonate components to yield the oxide.

Occurrence and applications

Na2O is not typically found as a free mineral; it occurs transiently in high-temperature processes and as a component of slags, glasses, and cements. In glass and ceramic production, it functions as a flux and a source of alkali to modify melting behavior. It is also used in laboratories as a strong base and a reagent in various synthetic contexts, though it is usually handled indirectly via its conversion to NaOH or sodium salts.

Safety

Sodium oxide is caustic and reacts with moisture and acids, releasing heat and caustic products. It should be handled with appropriate personal protective equipment and stored in dry, well-sealed containers to prevent hydration.