Thermonatrite
Thermonatrite | |
---|---|
Villiaumite with a white encrustation of Thermonatrite | |
General and classification | |
chemical formula | Na 2 [CO 3 ] • H 2 O |
Mineral class (and possibly department) |
Carbonates (and relatives) |
System no. to Strunz and to Dana |
5.CB.05 ( 8th edition : V / D.02) 01/15/01/01 |
Crystallographic Data | |
Crystal system | orthorhombic |
Crystal class ; symbol | rhombic-pyramidal mm 2 |
Room group (no.) | Pca 2 1 (No. 29) |
Lattice parameters | a = 10.72 Å ; b = 5.26 Å; c = 6.47 Å |
Formula units | Z = 4 |
Physical Properties | |
Mohs hardness | 1 to 1.5 |
Density (g / cm 3 ) | measured: 2.255 (synthetic); calculated: 2.262 |
Cleavage | Please complete |
colour | colorless, white, gray-yellow |
Line color | White |
transparency | transparent to translucent |
shine | Glass gloss, matt |
Crystal optics | |
Refractive indices |
n α = 1.420 n β = 1.506 n γ = 1.524 |
Birefringence | δ = 0.104 |
Optical character | biaxial negative |
Axis angle | 2V = measured: 48 °; calculated: 46 ° |
Other properties | |
Chemical behavior | water soluble; already soluble in weak acids with elimination of CO 2 |
Special features | alkaline (lye-like, soapy) taste, readily dehydrated |
Thermonatrite is a rarely occurring mineral from the mineral class of the " carbonates ( and relatives )". It crystallizes in the orthorhombic crystal system with the composition Na 2 [CO 3 ] • H 2 O. From a chemical point of view, it is a hydrous sodium carbonate . It is mainly found in the form of white or gray-yellow, powdery crusts and efflorescence. It also very rarely develops colorless to white, needle-like crystals .
Special properties
Since thermonatrite is on the one hand easily soluble in water, but on the other hand also readily dehydrated in the air, i.e. it splits off water of crystallization and dries out, it must be kept protected as a mineral sample in an airtight container.
Etymology and history
Thermonatrite was named in 1845 by Wilhelm Ritter von Haidinger , who named the mineral after the Greek word θερμός [thermós] for warm and the related mineral soda or the chemical compound soda , alluding to its origin as "soda dried out by the addition of heat".
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the thermonatrite belonged to the common mineral class of "carbonates,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 , Gaylussit , Pirssonit , Soda and Trona formed an independent group V / D.02 .
The 9th edition of Strunz's mineral systematics, valid since 2001 and used by the International Mineralogical Association (IMA), assigns thermonatrite 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.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns thermonatrite to the common class of "carbonates, nitrates and borates", like the old Strunz'sche systematics, but there it belongs to the category of "hydrous carbonates". Here he is to be found as the only member of the unnamed group 01/15/01 within the subdivision of " Water-containing carbonates with A + (XO 3 ) • x (H 2 O) ".
Education and Locations
Thermonatrite usually forms on the bottoms of salt lake and evaporite - deposits rare, even in volcanic fumaroles and hydrothermal veins related species carbonatites . Accompanying minerals include halite , soda and trona .
In total, Thermonatrite has so far (as of 2011) been detected at around 50 sites. In Austria the mineral was found on the Tyrolean Gratlspitze and in Switzerland it was found in the salt mines near Bex in the canton of Vaud.
Further sites are the Wadi Natrun in Egypt; Canton of San Juan (province of Nor Lípez) and Laguna Kollpa ( province of Sur Lípez ) in Bolivia; Damxung and Inner Mongolia in China; Narsaq in Greenland; Mont Saint-Hilaire ( Montérégie Hill ) in Canada; several places in the Great Hungarian Plain , Szeged and Debrecen in Hungary; of Mount Vesuvius in Italy; the Lake Bogoria and the volcano Suswa in the Rift Valley in Kenya; the Mandara Lake in the Libyan region Fessan ; Antsirabe in Madagascar; Tolbatschik on Kamchatka , several places on the Kola peninsula and Verkhne-Chusovskie Gorodki in the Urals in Russia; of Lake Natron in Tanzania and several salt lakes and salt mines in the US states of California , Michigan , Nevada , New Mexico , Oregon , Utah and Washington .
Synthetic manufacture
Thermonatrite can also be produced artificially with the help of a solution of sodium hydrogen carbonate which is saturated at 25 ° to 37 ° C and which is slowly cooled. If the solution is less saturated and at a lower temperature, however, soda crystals will develop.
Crystal structure
Thermonatrite crystallizes orthorhombically in the space group (space group no. 29) with the lattice parameters a = 10.72 Å ; b = 5.26 Å and c = 6.47 Å and 4 formula units per unit cell .
See also
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 - Thermonatrite (English)
- ↑ a b c Thermonatrite at mindat.org (engl.)
- ^ William Phillips, Henry James Brooke, William Hallows Miller: An elementary introduction to mineralogy, 1852, p. 600
literature
- Thermonatrite in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( PDF , 65.3 kB).
- Philipp Schwarzenberg: The technology of chemical products which are obtained from inorganic materials by large-scale operations, 1865, p. 185
Web links
- Mineral Atlas: Thermonatrite (Wiki)