Sodium bicarbonate

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Sodium bicarbonate
Natrite.jpg
General and classification
other names
chemical formula γ-Na 2 [CO 3 ]
Mineral class
(and possibly department) 		Carbonates and nitrates
System no. to Strunz
and to Dana 		5.AA.10 ( 8th edition : V / B.01)
01/14/06/01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / m (No. 12)Template: room group / 12
Lattice parameters a  = 8.90  Å ; b  = 5.24 Å; c  = 6.04 Å
β  = 101.2 °
Formula units Z  = 4
Physical Properties
Mohs hardness 3 to 3.5
Density (g / cm 3 ) measured: 2.54; calculated: 2.55
Cleavage perfect according to {001}, good according to {100} and {110}
colour colorless, light yellow to yellow-orange, light pink
Line color White
transparency transparent
shine Glass gloss, matt
Crystal optics
Refractive indices n α  = 1.410
n β  = 1.535
n γ  = 1.543
Birefringence δ = 0.133
Optical character biaxial negative
Axis angle 2V = 28 ° (measured), 26 ° (calculated)
Other properties
Chemical behavior Water soluble

Soda is a rarely occurring mineral from the mineral class of "carbonates and nitrates" with the chemical composition γ-Na 2 [CO 3 ] and is therefore chemically a sodium carbonate .

Soda crystallizes in the monoclinic crystal system and develops pseudo-hexagonal crystals up to about one centimeter in size. In its pure form, sodium bicarbonate is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also appear white and, due to foreign admixtures, take on a light yellow to yellow-orange, light pink color. Fresh samples show a glass-like gloss on the crystal surfaces . After a while, however, the mineral turns gray-white and becomes matt.

Etymology and history

Sodium was first discovered in drill cores near Olenii (Oleny) Ruchei, from Raswumtschorr and from Karnassurt in the Chibinen on the Russian Kola Peninsula . The mineral was described in 1982 by AP Khomyakov, who named it after its composition ( containing sodium ).

classification

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , natrite belonged to the common mineral class of "carbonates, nitrates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

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 natrite to the newly defined class of "carbonates and nitrates" (the borates form a separate class here), but also in there the division of “carbonates without additional anions; without H 2 O “. However, this is further subdivided according to the affiliation of the cations involved to certain element groups , so that the mineral according to its composition can be found in the subdivision "alkali carbonates", where together with gregoryite the "sodium gregoryite group" with the system -No. 5.AA.10 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns sodium nitride, like the outdated Strunz system, to the common class of “carbonates, nitrates and borates” and there to the “anhydrous carbonates” category. Here he can be found together with Zabuyelit in the unnamed group 01/14/06 within the sub-section “Anhydrous carbonates with simple formula A + CO 3 ”.

Crystal structure

Sodium crystallizes monoclinically in the space group C 2 / m (space group no. 12) with the lattice parameters a  = 8.90  Å ; b  = 5.24 Å; c  = 6.04 Å and β = 101.2 ° and 4 formula units per unit cell . Template: room group / 12

properties

The mineral is soluble in water and forms a strongly alkaline solution.

Education and Locations

Soda forms in pegmatite in differentiated alkaline massifs. As Begleitminerale occur among other thermonatrite , vinogradovite , Shortite , Pirssonit , Gaylussite , Nacaphit , natrosilite , Villiaumit , Neighborit , Rasvumit , Lomonosovit , Pektolith , sodalite and Fluorcaphit on.

As a rare mineral formation, natrite could only be detected at a few sites. In addition to its type localities in the Chibinen, the mineral was also found in Russia on the Tolbachik volcano on the Kamchatka Peninsula in the Far East .

Other previously known sites are in Canada, Austria, Italy and the USA.

See also

literature

  • AP Khomyakov: Natrite, Na 2 CO 3 - a new mineral . In: International Geology Review . tape 25 , no. 9 , 1983, pp. 1111-1116 , doi : 10.1080 / 00206818309466809 .
  • NV Zubkova, D. Yu. Pushcharovsky, G. Ivaldi, G. Ferraris, IV Pekov, NV Chukanov: Crystal structure of natrite, γ-Na 2 CO 3 . In: New yearbook for mineralogy, monthly books . tape 2 , 2002, p. 85–96 ( ferraris-prarolo.com [PDF; 215 kB ; accessed on November 30, 2017]).

Web links

Individual evidence

  1. ↑ a b c d 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.  285 (English).
  2. ↑ a b c d e Natrite . 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; 66  kB ; accessed on November 30, 2017]).
  3. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  4. ↑ a b c d e Natrite. In: mindat.org. Hudson Institute of Mineralogy, accessed June 16, 2019 .
  5. ↑ Find location list for soda in the Mineralienatlas and Mindat