Lindbergite
| Lindbergite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | MnC 2 O 4 • 2H 2 O |
|
Mineral class (and possibly department) |
Organic compounds - oxalates |
|
System no. to Strunz and to Dana |
10.AB.05 ( 8th edition : IX / A.01) 01.50.03.03 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / c (No. 15) |
| Lattice parameters |
a = 11.995 Å ; b = 5.632 Å; c = 9.967 Å β = 128.33 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2.5 |
| Density (g / cm 3 ) | 2.1 |
| Cleavage | completely after (010) |
| Break ; Tenacity | uneven, crumbly |
| colour | white to gray |
| Line color | White |
| transparency | transparent |
| shine | Glass gloss |
| Other properties | |
| Chemical behavior | hardly soluble in water |
Lindbergite is a rarely occurring mineral from the mineral class of " organic compounds ". It crystallizes in the monoclinic crystal system with the composition MnC 2 O 4 · 2H 2 O, so from a chemical point of view it is a water-containing manganese (II) oxalate or the manganese salt of oxalic acid .
Lindbergite is transparent to opaque and rarely develops well-formed crystals with a tabular to prismatic habit . It is mostly found in the form of grape or fibrous to earthy aggregates and crusty coatings of yellow to brownish-yellow or amber-yellow color.
With a Mohs hardness of 2.5, lindbergite stands between the reference minerals gypsum and calcite . It is one of the soft minerals that can be easily scratched with a copper coin.
Etymology and history
The mineral was named after Marie Louise Lindberg from the USGS . Lindbergite has been listed as an officially recognized mineral by the IMA since 2003 under the number 2003-029. The first descriptors are: Daniel Atencio, José MV Coutinho, Stefan Graeser, Paulo A. Matioli and Luiz AD Menezes Filho.
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , lindbergite belonged to the mineral class of "organic compounds" and there to the department of "salts of organic acids", where together with Caoxit , Coskrenit- (Ce) , Glushinskit , Humboldtin , Levinsonit- (Y) , Minguzzit , Moolooit , Natroxalat , Novgorodovait , Oxammit , Stepanovit , Weddellite , Wheatleyite , Whewellite , Zhemchuzhnikovit and Zugshunstit- (Ce) the "group of oxalates [C 2 O 4 ] 2− " with the system -No. IX / A.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), also classifies lindbergite in the "Salts of organic acids" section. However, this is further subdivided according to the type of salt-forming acid , so that the mineral can be found in the sub-section "Oxalates" according to its composition, where it only forms the unnamed group 10.AB.05 together with Humboldtin .
The systematics of minerals according to Dana also assigns Lindbergite to the class of "organic minerals" and there in the department of the same name. Here he is with Glushinskit and Humboldtin in the "Humboldting group" with the system no. 50.01.03 within the sub-section “ Salts of organic acids (oxalates) ”.
Crystal structure
Lindbergite crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a = 11.995 Å ; b = 5.632 Å; c = 9.967 Å and β = 128.33 °, as well as four formula units per unit cell .
properties
Like all oxalates, lindbergite also decomposes when heated. First of all, the water of crystallization is released and at temperatures above 190 ° C it breaks down with the formation of manganese (II) carbonate and carbon monoxide .
Modifications and varieties
So far, no further modifications or varieties of Lindbergite have been found (as of February 2013). However, orthorhombic, prismatic crystals of lindbergite are known, which are believed to be pseudomorphoses based on an orthorhombic trihydrate of manganese oxalate. The trihydrate itself has not yet been described as a mineral (as of November 2013). In terms of these properties, Lindbergite is very similar to the hypothetical varieties of Humboldtin .
Education and Locations
Lindbergite occurs predominantly as a secondary mineral in pegmatites . It was first described for the Brazilian site Lavra da Boca in the state of Minas Gerais . Lindbergite is associated with triphyllite , phosphosiderite , frondelite , strictite , cyrilovite , bermanite , rockbridgeite , hureaulite , tavorite , reddingite , heterosite and laueit .
In the meantime it has been described for many localities. One of the most famous in Germany is the Clara mine in the Black Forest . A hitherto unknown manganese oxalate was described here even before Lindbergite was first described. Only later it turned out that this was Lindbergite.
Bat droppings or the introduction of fertilizers are often involved in the formation of lindbergite. These substances can react with minerals containing manganese such as pyrolusite and form lindbergite. The formation of lindbergite through fertilizer input has been documented for the Triberg site in the Black Forest.
Even if Lindbergite is the salt of an organic acid, no biological processes have to be involved in its formation. The formation of the Clara mine in the Black Forest is a controversial issue. However, anthropogenic influences can be excluded.
use
Due to the rarity of lindbergite, there are no practical uses for this mineral. The manganese (II) oxalate used in the chemical industry is produced exclusively synthetically.
See also
Web links
- Mineral Atlas: Lindbergite (Wiki)
- Lindbergite on Mindat
- Mineralogical Association of Canada (data sheet) (PDF; 23 kB)
Individual evidence
- ↑ Webmineral - Lindbergite
- ↑ a b c d Takuya Echigo, Mitsuyoshi Kimata: Single-crystal X-ray diffraction and spectroscopic studies on humboldtine and lindbergite: weak Jahn – Teller effect of Fe 2+ ion. In: Physics and Chemistry of Minerals. Volume 35, Edition 8 (2008), pp. 467–475, doi: 10.1007 / s00269-008-0241-7 ( PDF )
- ↑ a b c Zoe AD Lethbridge, Aileen F. Congreve, Emma Esslemont, Alexandra MZ Slawin, Philip Lightfoot: Synthesis and structure of three manganese oxalates: MnC 2 O 4 · 2H 2 O, [C 4 H 8 (NH 2 ) 2 ] [Mn 2 (C 2 O 4 ) 3 ] and Mn 2 (C 2 O 4 ) (OH) 2 . In: Journal of Solid State Chemistry . Volume 172, Issue 1, April 2003, pp. 212-218, doi: 10.1016 / S0022-4596 (03) 00035-5 (abstract)
- ^ Daniel Atencio, José MV Coutinho, Stefan Graeser, Paulo A. Matioli, Luiz AD Menezes Filho: Lindbergite, a new Mn oxalate dihydrate from Boca Rica mine, Galiléia, Minas Gerais, Brazil, and other occurrences. In: American Mineralogist. Volume 89 (3), pp. 1087-1091, doi: 10.2138 / am-2004-0721 ( Abstract HTML and Abstract PDF )
- ^ Philippe Roth: Minerals First Discovered in Switzerland and Minerals Named After Swiss Individuals . Excalibur Mineral Corp., 2007, ISBN 978-3-9807561-8-1 , pp. 99 ( limited preview in Google Book search).
- ↑ Michael E. Brown: Thermal Decomposition of Manganese (II) Oxalate in Vacuum and Oxygen. [ pdf; 532 kB ( Memento from February 29, 2012 in the Internet Archive )], doi: 10.1039 / F19747001316
- ↑ A. Huizing, HAM van Hal, W. Kwestroo, C. Langereis, PC van Loosdregt: Hydrates of manganese (II) oxalate. In: Materials Research Bulletin. Volume 12, Edition 6, June 1977, pp. 605-611, doi: 10.1016 / 0025-5408 (77) 90069-1 (abstract)
- ↑ Takuya Echigo, Mitsuyoshi Kimata: Crystal chemistry and genesis of organic minerals: A review of oxalate and polycyclic aromatic hydrocarbon minerals. In: Canadian Mineralogist. December 2010, Volume 48, pp. 1329–1357, doi: 10.3749 / canmin.48.5.1329 (abstract)