Soda (mineral)
| soda | |
|---|---|
 |
|
| General and classification | |
| chemical formula | Na 2 [CO 3 ] • 10H 2 O |
|
Mineral class (and possibly department) |
Carbonates (and relatives) |
|
System no. to Strunz and to Dana |
5.CB.10 ( 8th edition : V / D.02) 01/15/02/01 |
| Similar minerals | Thermonatrite , Trona |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic m |
| Space group | Cc |
| Lattice parameters |
a = 12.83 Å ; b = 9.03 Å; c = 13.44 Å β = 123.0 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 1 to 1.5 |
| Density (g / cm 3 ) | measured: 1.478; calculated: 1.458 |
| Cleavage | clear after {001}, imperfect after {010} |
| Break ; Tenacity | shell-like, brittle |
| colour | colorless, white, gray, yellow |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.405 n β = 1.425 n γ = 1.440 |
| Birefringence | δ = 0.035 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 71 °; calculated: 80 ° |
| Pleochroism | colorless |
| Other properties | |
| Chemical behavior | water-soluble, soluble in weak acids with CO 2 emission |
| Special features | phosphorescent |
The or soda ( English soda ) is a salt - mineral from the mineral class of the " Carbonate ( and relatives )." It crystallizes in the monoclinic crystal system with the chemical composition Na 2 [CO 3 ] • 10H 2 O and thus represents the decahydrate of sodium carbonate .
Soda usually develops colorless, white, gray or yellow efflorescence or crusty coatings on salt rocks .
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , soda belonged to the common mineral class of "carbonates, nitrates and borates " and there to the department of "hydrous carbonates without foreign anions ", where it together with baylissite , chalconatronite , gaylussite , Pirssonite , Thermonatrite and Trona formed an independent group V / D.02 .
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns soda to the new class of "carbonates and nitrates" (the borates now form a separate class). There it still belongs to the division of “carbonates without additional anions; with H 2 O “. However, this section is even more precisely subdivided according to the size of the cations involved , so that the mineral, according to its composition, can be found in the sub-section "With large cations (alkali and alkaline earth carbonates)", where it is the only member of the unnamed group 5 .CB.10 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns soda like the old Strunz'sche systematics to the common class of "carbonates, nitrates and borates", but there in the department of "hydrous carbonates". Here he is to be found as the only member of the unnamed group 01/15/02 within the subdivision of " Water-containing carbonates with A + (XO 3 ) • x (H 2 O) ".
Modifications and varieties
Soda is one of seven modifications of the chemical compound sodium carbonate . The other modifications are:
- anhydrous sodium carbonate (Na 2 CO 3 , mineral natrite )
- Sodium carbonate monohydrate (Na 2 CO 3 • H 2 O, mineral: Thermonatrite )
- Sodium calcium carbonate dihydrate (Na 2 Ca (CO 3 ) 2 • 2H 2 O, mineral pirssonite )
- Sodium calcium carbonate pentahydrate (Na 2 Ca (CO 3 ) 2 • 5H 2 O, mineral gaylussite )
- Sodium carbonate heptahydrate (Na 2 CO 3 • 7 H 2 O)
- Sodium carbonate hydrogen carbonate dihydrate (Na (HCO 3 ) • Na 2 CO 3 • 2H 2 O, Mineral Trona ).
Education and Locations
Soda forms mainly through evaporation at the edges of salt lakes or through precipitation on the lake bed in cold weather.
It was found in various soda lakes in Egypt , Ethiopia ( Shala ), Bolivia ( San Juan ), Great Britain , Italy , Canada , Mongolia (East Gobi), Hungary , Russia , Switzerland and the USA .
Crystal structure
Soda crystallizes monoclinically in the space group Cc with the lattice parameters a = 12.83 Å ; b = 9.03 Å; c = 13.44 Å and β = 123.0 ° as well as 4 formula units per unit cell .
use
Already in ancient times it was generally used as a cleaning agent for glass, among other things. In ancient Egypt it was used to dry corpses and thus for mummification . The ancient Romans tried to bleach hair with alkaline birch ash or soda.
Soda is an important raw material or an important aid for the production of glass , bleaching agents , detergents , coloring agents , tannery products .
The natural occurrences are not sufficient for this, so that it is produced in large quantities worldwide (see sodium carbonate ).
See also
literature
- Martin Okrusch, Siegfried Matthes: Mineralogy: An introduction to special mineralogy, petrology and deposit science . 7th edition. Springer Verlag, Berlin, Heidelberg, New York 2005, ISBN 3-540-23812-3 , pp. 46, 306 .
Web links
- Mineral Atlas: Soda (Wiki)
- Mineral data sheet - Soda (English, PDF 66 kB)
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 304 .
- ↑ Webmineral - Natron (English)
- ↑ a b c d Natron at mindat.org (engl.)
- ↑ Duden, spelling of the German language; 21st ed .; Mannheim, Leipzig, Vienna, Zurich 1996
- ↑ Mineral data sheet - Natron (English; PDF; 68 kB)