Sodium Carbonate - Na2CO3

Na₂CO₃ 

Sodium carbonate, Na2CO3·10H2O, (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions in water. Historically, it was extracted from the ashes of plants growing in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood (once used to produce potash), sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process.

More about Sodium Carbonate in Wikipedia 

Formula: Na₂O₃·10H₂O

Molar mass: 286.1416 g/mol
Form: White solid, hygroscopic powder
CAS Number: 6132-02-1
Density: 1.46 g/cm³
Synonyms: Soda ash, washing soda, soda crystals, sodium trioxocarbonate, Calcined soda, Crystol carbonate, Natriumkarbonat, Bisodium carbonate decahydrate