|name, symbol, ordinal number||tellurium, width unit,52|
|group, period, block||16 (VIA), 5, p|
|appearance||silvery shining grey|
|proportion at the earth's crust||1 · 10 -6 %|
|atomic radius (computed)||140 (123) pm|
|Kovalenter radius||135 pm|
|vanthe Waals radius||206 pm|
|Elektronenkonfiguration||[Kr] 4 D 10 5 s 2 5p 4|
|electrons per energy level||2, 8, 18, 18, 6|
|1. Ionization energy||869.3 kJ/mol|
|2. Ionization energy||1790 kJ/mol|
|3. Ionization energy||2698 kJ/mol|
|4. Ionization energy||3610 kJ/mol|
|5. Ionization energy||5668 kJ/mol|
|6. Ionization energy||6820 kJ/mol|
|7. Ionization energy||13200 kJ/mol|
|state of aggregation||firmly|
|density (Mohshärte)||6240 kg/m 3 (2,25)|
|melting point||722.66 K (449.51 °C)|
|boiling point||1261 K (988 °C)|
|Molecular volume||20,46 · 10 -6 m 3 /mol|
|heat of vaporization||52.55 kJ/mol|
|heat of fusion||17.49 kJ/mol|
|steam pressure||23.1 Pa with 272,65 K|
|speed of sound||2610 m/s with 293,15 K|
|specific thermal capacity||202 j (kg · K)|
|Electrical conductivity||200 /m ohms|
|of heat conductivity||2,35 W (m · K)|
|oxidation conditions||±2, 4, 6|
|oxides (basicity)||TeO 2, TeO 3 (easily sourly)|
|normal potential||-1.143 V (width unit + 2e - → width unit 2)|
|Elektronegativität||of 2.1 (Pauling scale)|
| as far as possible and common, are used SI-UNITs.|
If not differently notes,
the indicated data apply with standard conditions.
Tellurium is a chemical element in the periodic system of the elements with the symbolWidth unit and the ordinal number 52. The brittle, silver-white metallically completeends metalloid from the group of the Chalkogene resembles in the appearance the tin. In the chemical behavior it stands for the sulfur and selenium close, although it possesses some (half) metallic characteristics.
Table of contents
tellurium (Latin tellus for earth) became 1782 by Franz JosephMueller von Reichenstein (1740-1825), in filter defiency guarantee, Romania discovers. During the investigation of Goldtellurit (aurum problematicum) a tellurium connection isolated from realm stone.
tellurium is a rarely occurring element. Also gold and silver come it gediegen as Telluridforwards.
Also some tellurhaltige minerals are well-known:
- Altait PbTe
- Hessit AG 2 width unit
- Krennerit or Calaverit AuTe 2
- Rickardit cu 4 width unit 3
- Sylvanit (“Schrifterz”) AuAgTe 4
- Tellurbismutit Bi 2 width unit 3
- Tellurit TeO 2
- Tetradymit Bi 2 width unit3 S
production and representation
industrialist one wins tellurium as by-product during the electrolytic copper and nickel production from the anode mud by Abrösten.
The reduction to elementary tellurium takes place electrolytically or via reduction with sulfur dioxide. Highly pure telluriumthrough one produces for zone floatings.
to characteristics tellurium in two modifications:
- amorphous tellurium; a brown powder, which can be precipitated by reduction from Telluriger acid by reduction with sulfurous acid. At ambient temperature transformation sets to metallic tellurium.
- metallic tellurium is insoluble in all solvents, with which it does not react chemically.
Tellurium steam is yellow.
Chemically tellurium behaves like the lighter group member selenium.
Tellurium melts attack copper, iron and stainless high-grade steel.
128 width unit is considered as the isotope with the slowest decay of all not-stable isotopes of all elements.
- additive for steel, cast iron, copper and lead alloys, as well as in stainlessHigh-grade steels.
- Curing aid
- photo - and solar cells (Cadmiumtellurid) to the generation of current
- of thermocouples for generation of current from Bismuttellurid with plutonium batteries as heat source
- of Peltier elements from Bismuttellurid
- in Chalkogenid - connections as phase change material as
- cartridges (blasting caps)
- ceramic(s) production
in the microbiology is used tellurithaltiger agar as selective growth medium and proof for staphylococci. The colonies appear as small black balls, there staphylococci Tellurit to metallic tellurium reduce and intheir cells store.
K 2 TeO 3 (colorless) + 6e ------> Te° (black)
tellurium and tellurium connections are poisonous.
Tellurium powder is inflammable, finely divided in air is explosive it. In analogy to the accompanying elements of the 5. Main groupArsenic and antimony (where the arsenic is more poisonous far than the antimony) however not as poisonous as selenium. In vivo inorganic compounds of tellurium are reduced large part to the element, however a small part is converted to Dimethyltellurid. This easily volatileConnection lends to the breathing air in case of the incorporation of inorganic tellurium connections an unpleasant garlic smell, also over the skin this connection is slowly separated.
- tellurium hydrogen H 2 width unit
- Tellurdioxid TeO 2
- Tellurtrioxid TeO of 3
- tellurium halides TeX 4 (X = F, Cl, Br, I), TeF of 6
- tellurium complexes [TeX 6] 2 - (X = F, Cl, Br, I), (NH 4) 2 [TeCl 6]
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