The or soda ( bicarbonate of soda English ) is a salt - mineral from the mineral class of " carbonates ( and relatives ) ." It crystallizes in the monoclinic crystal system with the chemical composition Na2 [ CO3 ] • 10H2O and thus represents the decahydrate of sodium carbonate

Soda usually develops colorless, white, gray or yellow efflorescence or crusty coatings on salt rocks.


In the now outdated but still in use 8th edition of the mineral classification by Strunz soda was part of the common mineral class of " carbonates, nitrates and borates " and then to the Department of " water -containing carbonates without foreign anions ", where it together with Baylissit, Chalkonatronit, Gaylussite, Pirssonit, thermonatrite and trona formed a distinct group V/D.02.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns soda in the new class of " carbonates and nitrates " (the borates now form a separate class ). There it still belongs to the department of " Carbonate without other anions, with H2O". This division, however, is more accurately classified by the size of the cations involved, so that the mineral is found according to its composition in the subsection "With large cations ( alkali and alkaline earth carbonates ) ," where it is the only member of the unnamed group 5 forms. CB.10.

The mostly commonly used in English-speaking classification of minerals according to Dana assigns the soda as the old Strunz'sche systematics in the common class of " carbonates, nitrates and borates ", There, however, in the department of " water -containing carbonates ". Here he is the only member of the unnamed group 15:01:02 within the sub-division of " water -containing carbonates with A ( XO3 ) • x (H2O) " to find.

Modifications and varieties

Soda is one of seven modifications of the chemical compound of sodium carbonate. The other modifications are the

  • Anhydrous sodium carbonate (Na2CO3, mineral Natrit )
  • Monohydrate (Na2CO3 • H2O, Mineral: thermonatrite )
  • Dihydrate ( Na2Ca ( CO3) 2 • 2H2O, mineral Pirssonit )
  • Pentahydrate ( Na2Ca ( CO3) 2 • 5H2O, mineral Gaylussite )
  • Heptahydrate (Na2CO3 • 7 H2O)
  • Hydrogen carbonate ( Na ( HCO3) • 2H2O Na2CO3 •, mineral trona ).

Education and Locations

Soda is mainly due to evaporation at the edges of salt lakes or by precipitation on the lake bottom in cold weather.

Locations are different soda lakes including in Egypt, Ethiopia ( Shala ), Bolivia (San Juan ), Great Britain, Italy, Canada, Mongolia (East Gobi ), Hungary, Russia, Switzerland and the USA.

Crystal structure

Soda crystallizes in the monoclinic space group Cc with lattice parameters a = 12.83 Å; b = 9.03 Å; c = 13.44 Å and β = 123.0 °, and four formula units per unit cell.


In ancient times it was commonly used as a cleaning agent for glass, among others. In ancient Egypt it was used for the drying of bodies and thus of mummification. Even the Romans in ancient times tried to bleach with alkaline ash or birch soda hair.

Soda ash is an important raw material or important tool for the production of glass, bleaches, detergents, dyes, tanning products.

The natural resources are not sufficient for it, so it is produced in large quantities worldwide (see sodium carbonate).