Trona (mineral)
| Trona | |
|---|---|
 |
|
| General and classification | |
| other names |
Urao |
| chemical formula | Na 3 (HCO 3 ) (CO 3 ) • 2H 2 O |
|
Mineral class (and possibly department) |
Carbonates and nitrates (formerly carbonates, nitrates and borates) |
|
System no. to Strunz and to Dana |
5.CB.15 ( 8th edition : V / D.02) 01/13/04/01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / c (No. 15) |
| Lattice parameters |
a = 20.42 Å ; b = 3.49 Å; c = 10.33 Å β = 106.4 ° |
| Formula units | Z = 4 |
| Frequent crystal faces | {001}, {100}; stretched to {010} |
| Physical Properties | |
| Mohs hardness | 2.5 to 3 |
| Density (g / cm 3 ) | measured: 2.11; calculated: 2.124 |
| Cleavage | completely after {100}, indistinct after { 2 11} and {001} |
| Break ; Tenacity | uneven to small mussels |
| colour | colorless, gray, yellow, gray-white, yellow-white, pink |
| Line color | White |
| transparency | translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.412 n β = 1.492 n γ = 1.540 |
| Birefringence | δ = 0.128 |
| Optical character | biaxial negative |
| Axis angle | 2V = 72 ° (measured); 70 ° (calculated) |
| Other properties | |
| Chemical behavior | water-soluble, soluble in weak acids with CO 2 emission |
Trona is a rarely occurring mineral from the mineral class " carbonates and nitrates " (formerly carbonates, nitrates and borates , and relatives ). It crystallizes in the monoclinic crystal system with the composition Na 3 (HCO 3 ) (CO 3 ) · 2H 2 O, so it is chemically a water-containing sodium hydrogen carbonate .
Trona mostly develops translucent crystals with a columnar or fibrous habit , but also massive aggregates of white, gray, yellow and occasionally pink color including all intermediate tones. Colorless crystals are also known.
Etymology and history
The name Trona is derived from the Arabic word "trōn", which is the shortened form of natrūn and an abbreviation for soda ( sodium hydrogen carbonate ). Its root word is, however, even older. It can also be found in the Hebrew נטרן (natruna) and in the older Greek word νιτρον (nitron, Aristotle) or Roman nitron (Pliny).
Trona was first described and named in 1773 by the Swedish consul Bagge in Tripoli, who found the mineral in Fessan (Fezzan, Libya).
The name alkali orientale impurum terrestre, introduced by Johan Gottschalk Wallerius in 1759 for a new mineral, is assigned to the Trona by various sources, but corresponds to the chemically similar thermonatrite .
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the trona belonged to the common mineral class of "carbonates, nitrates and borates " and there to the department of "hydrous carbonates without foreign anions ", where together with baylissite , chalconatronite , Gaylussite , pirssonite , soda and thermonatrite formed a separate group.
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 the Trona to the new class of "carbonates and nitrates" (the borates form a separate class here). There the mineral still belongs to the category of “carbonates without additional anions; with H 2 O “. However, this is now further subdivided according to the size of the cations involved and the element group of the metals, so that the mineral can be found in the sub-section “With large cations (alkali and alkaline earth carbonates)”, where it is the only member, according to its composition forms the unnamed group 5.CB.15 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Trona to the common class of "carbonates, nitrates and borates" and there in the department of "carbonates", like the outdated Strunzian system. Here he is to be found as the only member of the unnamed group 01/13/04 within the subdivision of “ 01/13 Acid Carbonates with Different Formulas ”.
Crystal structure
Trona crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a = 20.42 Å ; b = 3.49 Å; c = 10.33 Å and β = 106.4 ° and 4 formula units per unit cell .
properties
Trona can show greenish to yellowish-green fluorescence under UV light .
Trona is water-soluble and has an alkaline ("soapy") taste. It is also soluble in weak acids with the release of CO 2 .
Education and Locations
Trona forms in non-oceanic evaporites and is therefore mainly found in salt lakes ( soda lakes ) in many desert areas. It is also rarely found in the form of efflorescence from gases escaping from fumaroles . As accompanying minerals occur among others Bradleyit , glauberite , halite , mirabilite , sodium carbonate ( soda ), Northupit , Pirssonit , Shortite , thermonatrite , thenardite and in alkaline lakes gypsum .
As a rare mineral formation, Trona could so far (as of 2012) only be proven at a few sites, with around 100 sites being known.
The only known sites in Germany are the slag heaps of the Braubach lead and silver smelter in Rhineland-Palatinate. In Switzerland, Trona was found in the Bex salt mine in the canton of Vaud and during construction work on the tunnel construction for the national road 9 near Martigny in the canton of Valais.
Other locations include Egypt , Argentina , Australia , Bolivia , Chile , China , Greenland , Italy , Canada , Kenya , Libya , Namibia , Russia , South Africa , Sudan , Tanzania , Chad , the Czech Republic , Turkey , Uganda , Ukraine , Hungary , Venezuela , the United Kingdom (Great Britain) and the United States of America (USA).
use
Trona is an important mineral in the production of sodium carbonate . In addition to the ammonia-soda process ( Solvay process ) for the production of pure soda (Na 2 CO 3 ), the Trona process has continued to gain acceptance in the USA since 1952 . The last ammonia-soda factory after Solvay closed its doors in 1985.
See also
literature
- Helmut Schrätze, Karl-Ludwig Weiner: Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 554 .
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, Stuttgart 1978, ISBN 3-432-82986-8 , p. 581 .
- Martin Okrusch, Siegfried Matthes: Mineralogy. An introduction to special mineralogy, petrology and geology . 7th fully revised and updated edition. Springer Verlag, Berlin et al. 2005, ISBN 3-540-23812-3 , pp. 306 .
Web links
- Mineral Atlas: Trona (Wiki)
Individual evidence
- ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1979, ISBN 3-342-00288-3 , p. 718 .
- ↑ a b IMA / CNMNC List of Minerals - Trona (English, PDF 1.8 MB; p. 288)
- ↑ Webmineral - Trona
- ^ A b c 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. 305 .
- ↑ a b c d John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Trona , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 67.4 kB )
- ↑ a b c d Mindat - Trona
- ↑ a b Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 335 .
- ^ Helmut Schrätze, Karl-Ludwig Weiner: Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 553 .
- ↑ Open Library - Robert Jameson: A system of mineralogy, in which minerals are arranged according to the natural history method , 3rd edition 1820, p. 44
- ↑ Mineralogie ou Description générale des substances du regne mineral by Johann Gotschalk Wallerius in the Google book search
- ^ Bulletin - United States National Museum , Published 1877 by Smithsonian Institution Press
- ↑ Mindat: Examples of fluorescent trona, greenish yellow and greenish from Owens Lake, California, USA
- ↑ Mindat - Number of localities for Trona