Sylvin
| Sylvin | |
|---|---|
 |
|
| General and classification | |
| chemical formula | KCl |
|
Mineral class (and possibly department) |
Halides - Simple halides |
|
System no. to Strunz and to Dana |
3.AA.20 ( 8th edition : III / A.02) 01/09/01/02 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic hexakisoctahedral; 4 / m 3 2 / m |
| Space group | Fm 3 m (No. 225) |
| Lattice parameters | a = 6.29 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | {100}, occasionally also combinations with {111} |
| Twinning | after {111} |
| Physical Properties | |
| Mohs hardness | 2 |
| Density (g / cm 3 ) | measured: 1.993 (5); calculated: 1.987 |
| Cleavage | completely after {001} |
| Break ; Tenacity | uneven |
| colour | colorless to white, light gray, light blue, yellowish, reddish, violet |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| radioactivity | weakly radioactive |
| Other properties | |
| Chemical behavior | water soluble |
| Special features | bitter aftertaste |
Sylvin is a rather seldom occurring mineral from the mineral class of " halides ". It crystallizes in the cubic crystal system with the composition K Cl , so from a chemical point of view it is potassium chloride .
Sylvin usually develops cube-shaped or octahedral crystals and combinations. In its pure form it is colorless and transparent. However, due to multiple light refraction due to lattice construction defects or polycrystalline training, it can also appear white and, due to foreign admixtures, take on a light gray, light blue, yellowish to reddish or violet color.
Sylvin, together with halite and small amounts of other minerals, forms the rock sylvinite .
Etymology and history
Its name, which is still valid today, Sylvin, was given to the mineral in 1832 by François Sulpice Beudant , who named it after the Dutch physicist and chemist Franciscus Sylvius (actually Franz de le Boë or Franciscus de le Boë Sylvius , 1614–1672), where he actually named himself the KCl preparation Sel digestis de Sylvius (German digestive salt of Sylvius ), which is already known and used in medicine . Beudant also recorded other previously known synonyms for Sylvin in his notes: Muriate de Potasse , Chlorure de potassium , Salzsaures Kali , Sél fébrifuge and Sel marin régénéré .
The type locality is Vesuvius in Italy.
classification
Already in the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the sylvin belonged to the mineral class of "halides" and there to the department of "simple halides", where together with bromargyrite , carobbiite , chlorargyrite , halite and villiaumite it was the " Halit series “with the system no. III / A.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), classifies the sylvine in the somewhat more refined division of "simple halides without H 2 O". This is further subdivided according to the molar ratio of metal (M) to halogen (X), so that the mineral can be found according to its composition in the sub-section "M: X = 1: 1 and 2: 3", where it can be found together with Carobbiit, Griceit , Halit and Villiaumit the "Halitgruppe" with the system no. 3.AA.20 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Sylvin to the class and division of the same name of "halides". Here he is also together with Halit, Villiaumit, Carobbiit and Griceit in the "Halitgruppe" with the system no. 01/09/01 to be found in the subsection of " Anhydrous and hydrous halides with the formula AX ".
Crystal structure
Sylvin crystallizes isotypically with halite in the cubic crystal system in the space group Fm 3 m (space group no. 225) with the lattice parameter a = 6.29 Å and 4 formula units per unit cell .
properties
Due to the low content of the radioactive isotope 40 K , sylvine is classified as weakly radioactive and has a specific activity of around 16 Bq / g.
Sylvin is very easily soluble in water and tastes salty with a bitter aftertaste.
Education and Locations
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Potash salts are formed by crystallization of the substances dissolved in sea water only after the solubility product of calcium carbonate , gypsum and sodium chloride has already been exceeded. Since potassium and magnesium chlorides and sulfates are very easily soluble in water, seawater has to evaporate almost completely before potassium salts crystallize. This explains the rarity of potash deposits compared to rock salt deposits. Sylvin and sylvinite (rock made from halite, sylvin and sometimes other salt minerals) seem to be more likely to be formed by recrystallization from carnallitites through saturated sodium chloride solutions, the secondary products of which are sylvin (it) and a sodium chloride liquor enriched in magnesium ions. This conversion still takes place today (mostly unintentionally) in potash deposits and leads to the impairment of the remaining pillars of carnallitic potash deposits that were left behind during extraction. Sylvinite areas are found as particularly valuable marginal facies of the much more common carnallitic potash salts. Accompanying minerals are halite , carnallite and others.
As a rather rare mineral formation, sylvine can sometimes be abundant at different sites, but overall it is not very common. So far (as of 2018) around 280 sites are known to be known.
Locations used to be, among others, Staßfurt and Wathlingen . B. Neuhof-Ellers , Sondershausen, Zielitz and other potash deposits in Germany , Berezniki and Solikamsk in the Perm region in Russia , Kalusch in the Ukraine , in Saskatchewan in Canada and Salton Sea in the USA , as well as in all potash deposits that mine sylvinite.
use
Sylvin is used as a raw material for the chemical industry , especially for fertilizers. Certain crops (fruit) do not tolerate much chloride, so potassium sulfates are preferred for such fertilizers (e.g. made from polyhalite).
See also
literature
- Petr Korbel, Milan Novák: Mineral Encyclopedia (= Villager Nature ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 72 .
- Martin Okrusch, Siegfried Matthes: Mineralogy. An introduction to special mineralogy, petrology and geology . 7th, completely revised and updated edition. Springer, Berlin [a. a.] 2005, ISBN 3-540-23812-3 , pp. 46, 277, 307 .
Web links
- Mineral Atlas: Sylvin (Wiki)
- Mindat - Sylvite (English)
Individual evidence
- ↑ a b Webmineral - Sylvite (English)
- ^ A b c Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 150 .
- ^ Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 317-318 .
- ↑ a b c Sylvite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 60 kB ; accessed on November 28, 2018]).
- ↑ 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. 329 .
- ↑ FS Beudant: Sylvine, muriate de potasse . In: Traité Élémentaire de Minéralogie . tape 2 , 1832 ( rruff.info [PDF; 53 kB ; accessed on November 28, 2018]).
- ↑ Mindat - Number of locations for Sylvin (English)
- ↑ Find location list for Sylvin in the Mineralienatlas and Mindat