Arsenolite
| Arsenolite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | As 2 O 3 |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.CB.50 ( 8th edition : IV / C.02) 03/04/09/01 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic hexakisoctahedral; 4 / m 3 2 / m |
| Space group | Fd 3 m (No. 227) |
| Lattice parameters | a = 11.07 Å |
| Formula units | Z = 16 |
| Physical Properties | |
| Mohs hardness | 1.5 |
| Density (g / cm 3 ) | 3.87 to 3.88 |
| Cleavage | Well |
| Break ; Tenacity | shell-like |
| colour | white, light blue, light yellow to light red |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss to silk gloss |
| Crystal optics | |
| Refractive index | n = 1.755 |
| Optical character | isotropic |
| Other properties | |
| Chemical behavior | soluble in hydrochloric acid and hot water |
| Special features | very toxic, carcinogenic |
Arsenolite , also known as arsenic bloom or arsenic , is a mineral from the mineral class of oxides and hydroxides that rarely occurs in nature . It crystallizes in the cubic crystal system with the chemical composition As 2 O 3 and is therefore chemically arsenic (III) oxide .
Arsenolite usually develops kidney, stalactitic or earthy-powdery mineral aggregates , but also small, octahedral crystals up to about 2 cm in size from white, light blue or light yellow to light red when it is contaminated with realgar or auripigment .
Etymology and history
Arsenolite was first scientifically described in 1854 by James Dwight Dana , who named the mineral after its main component arsenic and the ancient Greek word λίθος lithos for 'stone'.
The type locality is the Sankt Andreasberg in the Harz (Lower Saxony), but the chemical compound and, above all, its toxicity had been known since ancient times.
→ see main article arsenic (III) oxide
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the arsenolite belonged to the mineral class of "oxides and hydroxides" and there to the department of "oxides with the molar ratio of metal: oxygen = 2: 3", where it together with bismite the "arsenolite bismite group" with system no. IV / C.02 and the other members Chrombismite , Dukeit , Senarmontit , Sillenit , Sphaerobismoit .
The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the IMA, also assigns arsenolite to the class of "oxides", but in the department of "oxides with the molar ratio of metal: oxygen = 2: 3, 3: 5 and comparable "a. In addition, this section is further subdivided according to the size of the cations involved , so that the mineral can be found according to its composition in the sub-section “With medium-sized cations”, where it only forms the unnamed group 4.CB.50 together with senarmontite .
The systematics of minerals according to Dana also assigns arsenolite to the class of "oxides and hydroxides" and there into the category of "oxides". Here it can be found, also together with Senarmontite in the unnamed group 04.03.09 within the subdivision of " Simple oxides with a cation charge of 3 + (A 2 O 3 ) ".
Crystal structure
Arsenolite crystallizes isotypically with senarmontite in the cubic crystal system in the space group Fd 3 m (space group no. 227) with the lattice parameter a = 11.07 Å and 16 formula units per unit cell .
The crystal structure of arsenolite consists of four flat, trigonal AsO 3 pyramids with arsenic on top. These pyramids are connected via shared oxygen atoms to form As 4 O 6 molecules, which in turn are held together by van der Waals forces .
properties
Arsenolite is one of the most toxic minerals and is clearly carcinogenic . Less than 0.1 g ingested orally can be fatal.
A white fog appears in front of the soldering tube on carbon and there is a smell of arsenic . The mineral is soluble in hydrochloric acid and hot water.
Education and Locations
Arsenolite forms secondarily as a weathering product (through oxidation ) on metallic arsenic or arsenic-containing sulfides e.g. B. in hydrothermal veins . But it can also be caused by coal fires . Besides realgar and auripigment, accompanying minerals include claudetite and erythrin .
Arsenolite has been detected at around 190 sites around the world so far (as of 2010). In Germany, in addition to his type locality Sankt Andreasberg, he could also be found near Bad Harzburg in the Harz Mountains (Lower Saxony), in several places and mines in the Black Forest (Baden-Württemberg), in the Hartkoppe quarry near Sailauf (Bavaria), in the Spessart and Odenwald (Hesse), in the mine dawn (Nordrhein-Westfalen), in the pit Friedrichssegen at Frücht (Rhineland-Palatinate), the Count Jost Christian mine and the Enlightened luck mine (Harz, Saxony-Anhalt) and several discovery locations in Saxony's Ore mountains found .
Other locations are Australia , Belgium , Bolivia , Chile , China , Finland , France , Greece , Ireland , Italy , Japan , Canada , Kazakhstan , Morocco , New Zealand , North Macedonia , Norway , Austria , Poland , Romania , Russia , Sweden , Switzerland , Slovakia , Slovenia , Spain , South Africa , the Czech Republic , Hungary , the United Kingdom (Great Britain) and the United States of America (USA).
Synthetic manufacture
Since the mineral occurs only rarely in nature, but the compound is still of great importance for the chemical industry, among other things for the production of rodent poisons and insecticides , it is therefore produced synthetically .
→ see main article arsenic (III) oxide
Precautions
Arsenolite or arsenic is classified as toxic ( H-phrases H300 fatal if swallowed , H410 very toxic to aquatic organisms with long-term effects ) and can cause cancer (H350). The orally ingested, lethal dose for humans can be less than 0.1 g.
Handling arsenolite requires special precautions, such as keeping locked up; Use protective gloves and eye protection; Do not eat, drink or smoke at work; Avoid release to the environment and dispose of as hazardous waste. When transporting relevant quantities, it falls under dangerous goods class 6.1 with hazard number 60 above UN number 1557.
See also
literature
- Arsenolites . 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; 67 kB ; accessed on November 17, 2018]).
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 509-510 (first edition: 1891).
- Petr Korbel, Milan Novák: Mineral Encyclopedia (= Villager Nature ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 81 .
Web links
- Mineral Atlas: Arsenolite (Wiki)
Individual evidence
- ^ 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. 197 .
- ↑ a b Mindat - Arsenolite (English)
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 509 (first edition: 1891).