Avicennit
Avicennit | |
---|---|
General and classification | |
chemical formula | Tl 2 O 3 |
Mineral class (and possibly department) |
Oxides and hydroxides |
System no. to Strunz and to Dana |
4.CB.10 ( 8th edition : IV / C.03) 03/04/08/01 |
Crystallographic Data | |
Crystal system | cubic |
Crystal class ; symbol | m 3 |
Space group | Ia 3 (No. 206) |
Lattice parameters | a = 10.547 Å |
Formula units | Z = 16 |
Physical Properties | |
Mohs hardness | 1.5 to 2.5 |
Density (g / cm 3 ) | measured: 8.9; calculated: 10.34 |
Cleavage | Please complete |
Break ; Tenacity | knitted to chopped up |
colour | grey black |
Line color | grey black |
transparency | opaque |
shine | metallic |
Other properties | |
Chemical behavior | soluble in acids |
Avicennite is a very rare mineral from the mineral class of oxides and hydroxides . It crystallizes in the cubic crystal system with the chemical composition Tl 2 O 3 and is therefore chemically thallium (III) oxide . The mineral forms up to a millimeter in size, partly octahedral crystals as well as porous grains and coatings on carlinite of a gray-black color.
Etymology and history
The mineral was found in 1958 by KN Karpowa, EA Konkowa, ED Larkin and WF Saweljew near Dzhuzumli in Samarkand Province in what is now Uzbekistan . They named it after the Persian doctor Avicenna .
classification
In the old (8th edition) and new systematics of minerals according to Strunz (9th edition) , which is also used by the International Mineralogical Association (IMA), the Avicennit belongs to the department of “Oxides with the molar ratio metal : oxygen = 2 : 3 “, whereby this department was expanded in the new Strunz'schen mineral systematics by the oxides with the molar ratio metal: oxygen = 3: 5 and comparable and also more precisely divided according to the size of the cations . Accordingly, the mineral is now in the sub-section “With medium-sized cations”. In both systems it forms a group with Bixbyit .
The systematics of minerals according to Dana also assigns the Avicennit to the class of oxides, but there in the division of "Simple oxides with a cation charge of 3+ and the general formula A 2 O 3 ", where it forms its own subgroup.
Education and Locations
Avicennit is formed either by oxidation of carlinite or by weathering in a hematite - calcite vein in silicified limestone . Depending on where it was found, it is associated with carlinite, hematite, quartz or parapierrotite .
Avicennit is very rare, only six sites are known so far. In addition to the type locality , the mineral was also found in He County in the Chinese province of Anhui and in Tibet in Lhorong County , Elko in the US state of Nevada , and in Tooele County in the US state of Utah . There is also a known site in Greece .
Crystal structure
Avicennite crystallizes in the cubic crystal system in the space group Ia 3 (space group number 206) with the lattice parameter a = 10.547 Å and 16 formula units per unit cell .
Precautions
Avicennite is one of the most toxic minerals due to its high thallium content , so great care should be taken when handling it.
See also
literature
- HH Otto, R. Baltrusch, H.-J. Brandt: Further evidence for Tl 3+ in Tl-based superconductors from improved bond strength parameters involving new structural data of cubic Tl 2 O 3 , 1993, Materialwissenschaftliche Kristallographie, TU Clausthal, doi : 10.1016 / 0921-4534 (93) 90382-Z
Web links
- Mineral Atlas: Avicennit
- Avicennit at mindat.org (English)
- Database-of-Raman-spectroscopy - Avicennite (English)
- American-Mineralogist-Crystal-Structure-Database - Avicennite (English)
Individual evidence
- ↑ a b c Avicennite. , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 68 kB , English)
- ↑ a b Mineralienatlas: Avicennit
- ↑ New Dana Classification of Oxide Minerals (English)
- ↑ Mindat - Avicennite (English)