Thermonatrite

Thermonatrite is a rarely occurring mineral from the mineral class of " carbonates ( and relatives ) ." It crystallizes in the orthorhombic crystal system with the composition Na2 [ CO3 ] • H2O. Chemically, it is a hydrous sodium carbonate. It is found mainly in the form of white or greyish-yellow, powdery crusts and efflorescence. Very rarely, he also developed colorless to white, needle-like crystals.

Special Features

Since thermonatrite one hand, readily soluble in water, on the other hand but also dehydrates readily in the air, that is crystal water is split off and dries out, it must be stored as a mineral sample in an airtight container protected.

Etymology and history

Named thermonatrite in 1845 by Wilhelm Ritter von Haidinger, of the mineral after the Greek word θερμός [ thermos ] for warm and the related mineral soda or soda chemical compound in allusion to its origin as " dried out by heating baking soda ."

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the thermonatrite " water -containing carbonates without foreign anions " belonged to the common mineral class of " carbonates, nitrates and borates " and then to the Department of where it together with Baylissit, Chalkonatronit, Gaylussite, Pirssonit, soda 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 the thermonatrite 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.05.

The mostly commonly used in English-speaking classification of minerals according to Dana assigns the thermonatrite 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 15:01:01 within the sub-division of " water -containing carbonates with A ( XO3 ) • x (H2O) " to find.

Education and Locations

Thermonatrite forms usually on the bottoms of the salt lake and evaporite deposits, rarely also of volcanic fumaroles and in hydrothermal veins from related carbonatites. Accompanying minerals include halite, soda and Trona.

Overall, thermonatrite so far (as of 2011) are detected in about 50 localities. In Austria, the mineral is found in the Tyrolean Gratlspitze and Switzerland occurred in the salt mines at Bex evident in the canton of Vaud.

Other localities are the Wadi Natrun in Egypt; Canton of San Juan ( province Nor Lípez ) and Laguna Kollpa ( Lípez Sur Province) in Bolivia; Damxung and Inner Mongolia in China; Narsaq in Greenland; Mont Saint- Hilaire ( Montérégie hills ) in Canada; several places in the Great Hungarian Plain, Szeged and Debrecen in Hungary; Vesuvius in Italy; the Lake Bogoria and the volcano Suswa in the Rift Valley in Kenya; Mandara Lake in the Libyan Fezzan region; Antsirabe in Madagascar; Tolbachik on Kamchatka, several places on the Kola Peninsula and Verkhne- Chusovskie Gorodki in the Urals in Russia; Natron in Tanzania and several salt lakes and salt mines in the U.S. states of California, Michigan, Nevada, New Mexico, Oregon, Utah and Washington.

Synthetic production

Thermonatrite can also be artificially with the help of a solution saturated at 25 ° to 37 ° C solution of sodium hydrogen carbonate, which is slowly cooled to produce. In a less saturated solution at a lower temperature, however, crystals develop from soda.

Crystal structure

Thermonatrite crystallizes in the orthorhombic space group ( Raumgruppen-Nr. 29) with the lattice parameters a = 10.72 Å; b = 5.26 Å and c = 6.47 Å and four formula units per unit cell.