Silver telluride

Crystal structure
__ Ag      __ Te
General
Surname	Silver telluride
other names	Hessite (mineral) Silver (I) telluride
Ratio formula	Ag 2 Te
Brief description	black solid
External identifiers / databases
CAS number 12002-99-2 EC number 234-419-7 ECHA InfoCard 100.031.277 PubChem 6914515 Wikidata Q906709
properties
Molar mass	343.34 g mol −1
Physical state	firmly
density	8.35 g cm −3
Melting point	955 ° C
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Thermodynamic properties
ΔH f 0	−20.9 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Silver telluride (silver (I) -telluride, Ag ₂ Te) is a monoclinic crystal compound from the group of tellurides , which is formed from silver and tellurium . In a broader sense, the term silver telluride also includes metastable silver (II) telluride (AgTe), also referred to in mineral form as empressite , and Ag ₅ Te ₃ into which the metastable silver (II) telluride breaks down.

Extraction and presentation

Silver telluride is produced by passing tellurium vapors over silver in nitrogen gas at a reaction temperature of 470 ° C.

${\displaystyle \mathrm {2\ Ag+Te\longrightarrow Ag_{2}Te} }$

properties

Silver telluride is a black-gray, crystalline substance. The normal β-silver telluride has a monoclinic crystal structure with the space group P 2 ₁ / c (space group no. 14) and lattice constants of a = 816 pm, b = 446.8 pm, c = 897.7 pm and β = 124 ° 16 '. The α-modification has a cubic crystal structure with the space group Fm 3 m (No. 225) , and forms at temperatures above 144 ° C. In addition, three high-pressure modifications are known which form at pressures of 2.4 GPa, 2.8 GPa and 12.8 GPa.

Silver telluride is a semiconductor that can be both p- doped and n-doped.

use

Silver telluride is used to manufacture tellurium because it is a by-product (in addition to gold telluride ) when processing the anode sludge in copper refining.

Individual evidence

1. ^ ^{A b} Dale L. Perry: Handbook of Inorganic Compounds, Second Edition . CRC Press, 2011, pp. 486 ( limited preview in Google Book search).
2. ↑ ^{a b c} data sheet Silver (I) telluride from Sigma-Aldrich , accessed on August 7, 2011 ( PDF ).
3. ↑ ^{a b c} Georg Brauer (ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 1001.
4. ^ A. van der Lee, JL de Boer: Redetermination of the structure of hessite, Ag ₂ Te-III. In: Acta Crystallographica Section C Crystal Structure Communications. 49, pp. 1444-1446, doi : 10.1107 / S0108270193003294 .
5. ↑ Zhao Zhao, Shibing Wang, Haijun Zhang, Wendy L. Mao: Pressure-induced structural transitions and metallization in Ag ₂ Te. In: Physical Review B. 88, 2013, S., doi : 10.1103 / PhysRevB.88.024120 .
6. ↑ Seilnacht: Tellurium