Natriumcarbonat10H2O

Natriumcarbonat10H2O is the decahydrate form of sodium carbonate, with the chemical formula Na2CO3·10H2O. It crystallizes as colorless, transparent crystals that dissolve readily in water to give a strongly alkaline solution. The compound is commonly marketed as washing soda and is a widely used hydrated salt of sodium carbonate.

Natural occurrence and history

The naturally occurring mineral form of this compound is natron, a decahydrate of sodium carbonate found in arid regions and ancient lake beds. Natron has historical significance in ancient Egypt, where it was used for cleansing and mummification. Today, natron deposits are a minor source compared with synthetic production, but the decahydrate form remains an important industrial and household material.

Chemistry and properties

Natriumcarbonat10H2O consists of Na2CO3 units bound with ten water molecules. It is highly soluble in water and yields a basic (alkaline) solution. Upon heating, the decahydrate loses its water of crystallization and converts to anhydrous sodium carbonate (Na2CO3). In very dry air, it can slowly lose water and shift to lower hydrates or the anhydrous form. The solution typically has a pH around 11, reflecting its strong basicity.

Production and occurrence

In industry, sodium carbonate is mainly produced via the Solvay process; the decahydrate can be crystallized from solutions containing sodium carbonate and water, or obtained from natural natron deposits. Commercially sold washing soda crystals are commonly the decahydrate form.

Uses

Natriumcarbonat10H2O is used as a cleaning agent and laundry additive, for water softening, and for pH adjustment in various processes and products. It also serves as a chemical reagent in laboratories and has historical applications as a glass-making flux.

Safety and handling

It is an irritant to skin, eyes, and the respiratory tract in some exposures. Use appropriate protective equipment to avoid contact with eyes and prolonged inhalation of dust. Store in a sealed container away from acids; reactions with acids release carbon dioxide. Ingestion should be limited, and large amounts may cause digestive irritation.