Arsenic (III) selenide

Crystal structure
__  As 3+      __  Se 2−
Crystal system	monoclinic
Space group	P 2 1 / n (No. 14, position 2)
Lattice parameters	a = 1207.74 pm b = 990.37 pm c = 428.35 pm β = 90.458 °
General
Surname	Arsenic (III) selenide
other names	Arsenic triselenide
Ratio formula	As 2 Se 3
Brief description	brown odorless solid
External identifiers / databases
CAS number 1303-36-2 EC number 215-119-5 ECHA InfoCard 100.013.745 PubChem 14772 Wikidata Q4119943
properties
Molar mass	386.7 g mol −1
Physical state	firmly
density	4.75 g cm −3
Melting point	360 ° C
solubility	almost insoluble in water
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 301-331-373-410 P: 260-264-301 + 310-304 + 340-311-403 + 233
Toxicological data	> 5000 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Arsenic (III) selenide (As ₂ Se ₃ ) is a selenide formed from the two chemical elements arsenic and selenium .

Extraction and presentation

Arsenic (III) selenide can be obtained by reacting the elements in a vacuum at temperatures above 200 ° C.

${\displaystyle \mathrm {2\ As+3\ Se\longrightarrow As_{2}Se_{3}} }$

properties

Arsenic (III) selenide is a glossy black, brittle granulate or flaky powder that is practically insoluble in water. It is unstable at elevated temperature. As they are easy to oxidize, the presence of arsenic and selenium oxide must always be expected. The melting point of the amorphous substance in the absence of air is 360 ° C. Arsenic (III) selenide has a monoclinic crystal structure with the space group P 2 ₁ / n (space group no. 14, position 2) . However, there are still two high-pressure modifications, the first of which has a monoclinic crystal structure with the space group C 2 / m (space group no. 12) .

use

Arsenic triselenide is used as a light-sensitive coating and as a photoconductor on the surface of the transfer drum in devices used in electrophotography such as copiers and laser printers . Arsenic selenide is used as a chalcogenide glass for infrared optics because it transmits light with wavelengths between 870 nm and 17,200 nm.

Individual evidence

1. ↑ AC Stergiou, PJ Rentzeperis: The crystal structure of arsenic selenide, As ₂ Se ₃ . In: Zeitschrift für Kristallographie , 1985 , 173 , pp 185-191 doi : 10.1524 / zkri.1985.173.3-4.185
2. ↑ ^{a b c d e} data sheet Arsenic (III) selenide, 99.999% (metals basis) from AlfaAesar, accessed on October 24, 2013 ( PDF )(JavaScript required) .
3. ↑ ^{a b c d} Entry on arsentriselenide in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .
4. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entries on arsenic compounds, with the exception of those specified elsewhere in this Annex and selenium compounds with the exception of cadmium sulphoselenide and those specified elsewhere in this Annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on March 18, 2017. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ↑ Moriaki Wakaki, Takehisa Shibuya, Keiei Kudo (deceased): Physical Properties and Data of Optical Materials . CRC Press, 2007, ISBN 978-1-4200-1550-8 , pp. 30 ( limited preview in Google Book search).
6. ↑ Roger Blachnik (Ed.): Paperback for chemists and physicists . Volume III: Elements, Inorganic Compounds and Materials, Minerals . founded by Jean d'Ans, Ellen Lax. 4th, revised and revised edition. Springer, Berlin 1998, ISBN 3-540-60035-3 , pp. 308 ( limited preview in Google Book search).
7. ^ Z. Borisova: Glassy Semiconductors . Springer Science & Business Media, 2013, ISBN 978-1-4757-0851-6 , pp. 191 ( limited preview in Google Book search).
8. ↑ Patent EP26384 : Method for smoothing a photoconductive layer consisting of As ₂ Se ₃ . Registered on September 12, 1980 , published on April 8, 1981 , applicant: Siemens Aktiengesellschaft, inventor: Eberhard Bayer, Karl Kempter, Hauke ​​Harms, Andreas Meyer. ‌