Wegscheiderit

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Wegscheiderit
General and classification
other names

IMA 1967 special procedure

chemical formula
  • Na 5 H 3 (CO 3 ) 4
  • Na 5 H 3 [CO 3 ] 4
  • Na 5 (HCO 3 ) 3 (CO 3 )
  • (Na 2 CO 3 3NaHCO 3 )
Mineral class
(and possibly department) 		Carbonates and nitrates - carbonates without additional anions; without H 2 O
System no. to Strunz
and to Dana 		5.AA.30 ( 8th edition : Vb / A.01)
01/13/06/01
Crystallographic Data
Crystal system triclinic
Crystal class ; symbol triclinic pinacoidal; 1
Space group P 1 (No. 2)Template: room group / 2
Lattice parameters a  = 3.4762  Å ; b  = 10.0393 Å; c  = 15.5969 Å,
α  = 107.770 °; β  = 95.589 °; γ  = 95.028 °
Formula units Z  = 2
Physical Properties
Mohs hardness 2.5 to 3
Density (g / cm 3 ) 2.341 (measured); 2.32 to 2.334 (calculated)
Cleavage clear, prismatic
Break ; Tenacity uneven to half-mussel; no information in the literature
colour colorless, pale pink to brownish
Line color no information in the literature, according to the mineral color probably white
transparency translucent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.433
n β  = 1.519
n γ  = 1.528
Birefringence δ = 0.095
Optical character biaxial negative
Axis angle 2V = 32.4 (measured); 2V = 34 ° (calculated)
Pleochroism unavailable
Other properties
Chemical behavior soluble in warm H 2 O, less soluble in cold H 2 O; rapid decomposition in all common acids with development of CO 2

Wegscheiderite is a very seldom occurring mineral from the mineral class " carbonates and nitrates " (formerly carbonates, nitrates and borates ). It crystallizes in the triclinic crystal system with the idealized chemical composition Na 5 H 3 (CO 3 ) 4 , and is thus chemically seen a sodium - hydrogen - carbonate , according to a different view is a sodium hydrogencarbonate carbonate.

Wegscheiderit develops subidiomorphic, needle-like to leafy crystals up to 5 cm in size as well as fibrous and granular mineral aggregates . It is often found in pseudomorphoses according to Trona .

The type locality of Wegscheiderits is the " Green River Formation " durchteufende exploratory drilling "Perkins Well No. 1 "( coordinates of the Perkins Well No. 1 well ) in the area of ​​a lacustrine Trona deposit on the west bank of the Green River dammed up to the Flaming Gorge Reservoir , approx. 30 km south-southwest of Green River in Sweetwater County , Wyoming , United States .

Etymology and history

Rudolf Wegscheider - namesake for the Wegscheiderit. The bronze bust is in the arcade courtyard of the University of Vienna.

As early as 1960, Charles Milton and Joseph J. Fahey were familiar with a total of 19 different carbonate minerals from the " Green River Formation " in the US states of Wyoming, Utah and Colorado . For one of them, which could not be assigned to any of the minerals known at the time, the chemical composition was determined using Na 2 CO 3 · 3NaHCO 3 . Just one year later, after the most important physical and optical properties had been determined by a team of American scientists headed by Joseph J. Fahey, KP Yorks and Daniel E. Appleman, the new mineral was included in the 1961 abstracts volume of the annual general meeting of the Geological Society of America published. In 1963 the mineral was first described scientifically by Joseph J. Fahey and KP Yorks in the US science magazine "The American Mineralogist".

They named the minerals by Rudolf Franz Johann Wegscheider (1859-1935), in the course of his investigation of the phase equilibria in the system Na in 1913. 2 CO 3 -NaHCO 3 -H 2 O, the synthetic component Na 2 CO 3 · 3NaHCO 3 was synthesized . The mineral was recognized as a mineral by the "Commission on New Minerals and Mineral Names" of the International Mineralogical Association (IMA) in a 1967 report that summarized the 129 initial descriptions from 1961 to 1964. As a result, Wegscheiderit does not have an IMA number, but is managed under the sum recognition "IMA 1967 sp" ( special procedure ).

The type of material for Wegscheiderit is under catalog number 117710 (Donation JJ Fahey, United States Geological Survey , 1965) in the collection of the Smithsonian Institution belonging to National Museum of Natural History in Washington, DC , USA , kept.

classification

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the Wegscheiderite belonged to the mineral class of "carbonates, nitrates and borates" and there to the division of "anhydrous carbonates [CO 3 ] 2− without foreign anions ", where it belonged together with Kalicinit , Nahcolith , Natrit , Teschemacherit and Zabuyelit the "Nahcolith Kalicinit Group" with the system no. V / B.01 formed.

In the last revised and updated Lapis mineral directory in 2018 , which is still based on the outdated system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , the Wegscheiderite received the system and mineral number. V / B.01-060 . In the “Lapis system”, this corresponds to the section “Anhydrous carbonates [CO 3 ] 2− , without foreign anions ”, where Wegscheiderite, together with zabuyelite, Nahcolite, Kalicinite, Teschemacherite and Natrite, is a group that is not further named (V / B.01 ) forms.

The 9th edition of Strunz's mineral systematics , which has been valid since 2001 and updated by the International Mineralogical Association (IMA) until 2009, assigns Wegscheiderite to the class of “carbonates and nitrates”, which has been reduced by the borates, and there to the “carbonates without additional” class Anions; without H 2 O “. This is further subdivided according to the group affiliation of the cations involved , so that the mineral can be found according to its composition in the sub-section "Alkali carbonates", where the unnamed group with the system no. 5.AA.30 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Wegscheiderite 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 01/13/06 within the subdivision “ Acid carbonates with various formulas ”.

Chemism

An analysis in which the contents of (CO 3 ) 2− and (HCO 3 ) 1− were determined directly via titration yielded (after subtracting 0.06% Cl, 0.36% H 2 O - and 4.38% organic material as well as recalculation to a conventional oxide analysis) 43.30% Na 2 O; 46.60% CO 2 and 10.00% H 2 O + . The formula Na 5 (HCO 3 ) 3 (CO 3 ) (or Na 5 H 3 (CO 3 ) 4 ) requires a content of 43.28% Na 2 O; 49.17% CO 2 and 7.55% H 2 O + .

The official IMA formula for Wegscheiderite is given as Na 5 H 3 (CO 3 ) 4 . The Strunz formula, Na 5 H 3 [CO 3 ] 4 , follows the IMA-compliant formula, but here, as usual, the anion group is given in square brackets.

The only combination of elements Na – H – C – O among the currently known minerals (as of 2019) shows, apart from Wegscheiderite, only Nahcolite, NaHCO 3 ; Soda , Na 2 CO 3 · 10H 2 O, thermonatrite , Na 2 CO 3 · H 2 O; and Trona, Na 3 H (CO 3 ) 2 · 2H 2 O, as well as the unnamed phases UM1959-02-CO: HNa , Na 2 CO 3 · H 2 O; UM1974-04-CO: HNa , Na 4 H 2 (CO 3 ) 3 • 1.5H 2 O; UM1990-12-CO: HNa , Na-COH (?); and Unnamed (MSH UK-98) , Na (CO 3 ), (OH); on.

Crystal structure

Spatial representation of the structure of Wegscheiderite in cation-centered polyhedral representation and standard crystallographic orientation. The blue outline shows the unit cell. Color legend:   __ Na __ C __ O __ H

Wegscheiderite crystallizes in the triclinic crystal system in the space group P 1 (space group no. 2) with the lattice parameters a = 3.4762  Å ; b = 10.0393 Å; c = 15.5969 Å; α = 107.770 °; β = 95.589 ° and γ = 95.028 ° as well as two formula units per unit cell . Template: room group / 2

The crystallographic properties of Wegscheiderite were first demonstrated by Daniel E. Appleman using single crystal and powder diffraction techniques on material from the “Grierson Well No.” which penetrated the Eocene “Green River Formation” in Wyoming. 1 "determined. Nelson G. Fernandes, Roland Tellgren and Ivar Olovsson presented a more recent work - the illustration of the structure of the Wegscheiderite is based on their work.

In the crystal structure of Wegscheiderite, planar (CO 3 ) 2− groups are linked by hydrogen bonds and form two independent [H 3 (CO 3 ) 4 ] 5− fragments, which are linked by Na [5,6,7] . There are four hydrogen bonds in the asymmetric unit, two of which are asymmetric and two are symmetric. Obviously, the two hydrogen atoms in the symmetrical bonds are not in inversion centers .

properties

morphology

At its type locality, Wegscheiderite forms countless tiny, arbitrarily arranged subidiomorphic, needle-like to leafy crystals in a nearly 8 cm thick layer. In the research well "Grierson Well No. 1, located 12.5 miles northwest of the type locality" 1 ”, Wegscheiderite was found in leafy to tabular crystals up to 5 cm in size in solid halite . The mineral is also known in the form of fibrous and coarse-grained mineral aggregates up to 1 cm in size.

physical and chemical properties

The crystals of Wegscheiderite are colorless or pale pink to brownish. Your line color is not specified in the original publication, but due to the mineral color it should be white, as stated in the mineral atlas. The surfaces of the translucent crystals show a characteristic glass-like sheen . According to this glass gloss, Wegscheiderite has a medium-high refraction ( n α  = 1.433; n β  = 1.519; n γ  = 1.528) and - like many carbonates - a high birefringence (δ = 0.095). In the transmitted light the biaxially negative Wegscheiderite is colorless and shows no pleochroism.

Wegscheiderit has a clear, prismatic cleavage . It breaks like amblygonite , with the fracture surfaces being uneven to half-mussel-shaped. There is no information on tenacity in the original publication. Wegscheiderite has a Mohs hardness of 2.5 to 3 and is one of the soft to medium-hard minerals that, like the reference mineral calcite (hardness 3), could be scratched with a copper coin. It is a little less easy to scratch with a fingernail than the reference mineral gypsum (hardness 2). The measured density for Wegscheiderite is 2.341 g / cm³, the calculated density 2.32 g / cm³ to 2.334 g / cm³.

Wegscheiderit is neither in the short wave still in the long-wave UV light , a fluorescent . The mineral is readily soluble in warm H 2 O, less readily in cold H 2 O. In all conventional acids , rapid decomposition takes place with the development of CO 2 . Small splinters melt when heated in the gas flame to form a colorless ball, which turns white when cooled.

Education and Locations

Wegscheiderite is a mineral that occurs at its type locality, a lacustrine Trona deposit, as a displacement of Trona. It is also found in alkaline rock - pegmatites such as on the 1051 m high mountain Alluaiw ( Russian Аллуайв ) in the Lowosero massif in the Lowosero tundra on the Russian Kola peninsula , Murmansk Oblast . In the "Lower Permian Fengcheng Formation" in the Mahu Valley, northwestern Junggar Basin (Dsungarisches pool) in the north of Xinjiang , China , himself Wegscheiderit place together with trona and Nacolith on the floor of on tuffs formed lakes in the form of upward growing crystalline aggregates with a shrub-like appearance that sit on the tuff or tuff-like substrate. The nature of this occurrence proves that the Wegscheiderite and the other Na carbonates precipitated in a calm, over- saturated brine basin without water inflows and crystallized further at the bottom of the basin.

Accompanying minerals of the Wegscheiderite at the type locality are trona and halite . On the Alluaiw mountain in the Lowosero massif, it can be found in the central area of ​​the pegmatite ruins together with cryolite , villiaumite and kogarkoite or with Nahcolith , Sidorenkoite , Shortite , Katapleit and Lorenzenite . In the "Lower Permian Fengcheng Formation" in north-western China, Northupite is one of the accompanying minerals of the pathway separating rock in addition to trona and nacolite .

As a very rare mineral formation, Wegscheiderite is only known from a few localities or in a small number of stages. The mineral has been described so far (as of 2019) from around 10 sites. The type locality of the Wegscheiderite is the exploratory borehole "Perkins Well No. 1 " which penetrated the Eocene " Green River Formation ". 1 “in the area of ​​a lacustrine Trona deposit on the west bank of the Green River dammed up to the Flaming Gorge Reservoir , approx. 30 km south-southwest of Green River in Sweetwater County , Wyoming , United States .

The other locations for Wegscheiderite are:

Locations from Germany , Austria and Switzerland are therefore unknown.

use

With a content of 74.0% Na 2 CO 3 ( soda ), Wegscheiderite is one of the richest minerals containing sodium carbonate. Soda is used worldwide a. in the glass production , in the paper and pulp industry as well as in the manufacture of detergents and soaps used. In addition, Wegscheiderite is also a sought-after mineral by systematically collecting mineral collectors.

See also

literature

  • Joseph J. Fahey, KP Yorks: Wegscheiderite (Na 2 CO 3 · 3NaHCO 3 ), a new saline mineral from the Green River Formation, Wyoming . In: The American Mineralogist . tape 48 , no. 3-4 , 1963, pp. 400–403 (English, rruff.info [PDF; 268 kB ; accessed on November 14, 2019]).
  • Elimination . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 67 kB ; accessed on November 14, 2019]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 564 (first edition: 1891).
  • Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 719 .

Web links

Individual evidence

  1. ↑ a b c d Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: September 2019. (PDF 2692 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, September 2019, accessed October 4, 2019 .
  2. ↑ a b c d e Wegscheiderite. In: mindat.org. Hudson Institute of Mineralogy, accessed November 14, 2019 .
  3. ↑ a b c d 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.  286 .
  4. ↑ a b c d e f Wegscheiderite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 67  kB ; accessed on November 14, 2019]).
  5. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad Joseph J. Fahey, KP Yorks: Wegscheiderite (Na 2 CO 3 3NaHCO 3 ), a new saline mineral from the Green River Formation, Wyoming . In: The American Mineralogist . tape 48 , no. 3-4 , 1963, pp. 400–403 (English, rruff.info [PDF; 268 kB ; accessed on November 14, 2019]).
  6. ↑ a b c d e f g h Nelson G. Fernandes, Roland Tellgren, Ivar Olovsson: Structure and electron density of pentasodium trihydrogentetracarbonate . In: Acta Crystallographica Section B . tape 46 , no. 4 , 1990, pp. 466-474 , doi : 10.1107 / S0108768190002579 (English).
  7. ↑ a b c d e Peter Kolesar, Jaromir Tvrdý: Tsar treasures: Minerals and sites in Russia, Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, Belarus and in Ukraine . Bode, Haltern am See 2006, ISBN 3-925094-87-3 , p. 82 .
  8. ^ Charles Milton, Joseph J. Fahey: Green River mineralogy - a historical account . In: Donald P. McGookey, Daniel N. Miller Jr. (Eds.): Overthrust Belt of Southwestern Wyoming and Adjacent Areas . 15th Annual Field Conference Guidebook. 1st edition. Wyoming Geological Association, Casper, WY 1960, p. 159-162 .
  9. ^ Joseph J. Fahey, KP Yorks, Daniel E. Appleman: Wegscheiderite, a new saline mineral from the Green River Formation, Wyoming . In: Geological Society of America, Abstracts Annual Meetings 1961 . GSA, Boulder 1961, pp. 48A-49A (English, rruff.info [PDF; 125 kB ; accessed on November 14, 2019]).
  10. ↑ International Mineralogical Association: Commission on new minerals and mineral names: Without . In: Mineralogical Magazine . tape 36 , no. 1 , 1967, p. 131-136 (English).
  11. ↑ Catalog of Type Mineral Specimens - W. (PDF 85 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed November 14, 2019 .
  12. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  13. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed September 25, 2019 .
  14. ↑ Minerals with Na, C, H, O. In: mindat.org. Hudson Institute of Mineralogy, accessed November 14, 2019 .
  15. ^ Daniel E. Appleman: X-ray crystallography of wegscheiderite (Na 2 CO 3 · 3NaHCO 3 ) . In: The American Mineralogist . tape 48 , no. 3-4 , 1963, pp. 404–406 (English, minsocam.org [PDF; 168 kB ; accessed on November 14, 2019]).
  16. ^ Stefan Schorn and others: Olekminskit. In: mineralienatlas.de. Retrieved November 14, 2019 .
  17. ↑ a b Kuanhong Yu, Yingchang Cao, Longwei Qiu, Peipei Sun, Xiyu Jia, Min Wan: Geochemical characteristics and origin of sodium carbonates in a closed alkaline basin: The Lower Permian Fengcheng Formation in the Mahu Sag, northwestern Junggar Basin, China . In: Palaeogeography, Palaeoclimatology, Palaeoecology . tape 511 , 2018, p. 506-531 , doi : 10.1016 / j.palaeo.2018.09.015 (English, researchgate.net [PDF; 12.9 MB ; accessed on November 14, 2019]).
  18. ↑ Localities for Wegscheiderite. In: mindat.org. Hudson Institute of Mineralogy, accessed November 14, 2019 .
  19. ↑ a b c List of locations where Wegscheiderite was found in the Mineralienatlas and Mindat (accessed on November 14, 2019)
  20. ↑ Wegscheiderite Market. In: www.marketresearchreports.biz. Market Research Reports, accessed November 14, 2019 .