Tellurium

characteristics
antimony - tellurium - iodine SE width unit Po [Kr] 4d 10 5s 2 5p 4 ,130 52 width unit < div id= " box2 " style= " boron that: solvently 1px black; position: absolute; top: 40px; left: 232px; width: 7px; height: 9px; OVERFLOW: hidden; “/> Periodic system
generally
name, symbol, ordinal number	tellurium, width unit,52
series	of metalloids
group, period, block	16 (VIA), 5, p
appearance	silvery shining grey
proportion at the earth's crust	1 · 10 -6 %
atomically
atomic mass	127.60
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
physically
state of aggregation	firmly
modifications	-
crystal structure	hexagonally
density (Mohshärte)	6240 kg/m 3 (2,25)
magnetism	non-magnetic
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)
Chemically
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)
isotopes
isotope NH t 1/2 ZM CPU M eV ZP 118 width unit {syn.} 6.00 D ε 0.278 118 self-service 119 width unit {syn.} 16.03 h ε 2.293 119 self-service 120 width unit 0.096% width unit is stable with 68 neutrons 121 width unit {syn.} 16.78 D ε 1.040 121 self-service 121 m width unit {syn.} 154 D IT ε 0.294 1.334 121 width unit 121 self-service 122 width unit 2.603% width unit is stable with 70 neutrons 123 width unit 0.908 >1 · 10 13 A ε 0.051 123 self-service 124 width unit 4.816% width unit is with 72 neutrons 125 width unit 7.139% width unit is stable stably with 73 neutrons 126 width unit 18.952% width unit is stable with 74 neutrons 127 width unit {syn.} 9.35 h β - 0.698 127 I 127 m width unit {syn.} 109 D IT β - 0.088 0.786 127 width unit 127 I 128 width unit 31.687 2,2 · 10 24 A β - β - 0.867 128 Xe 129 width unit {syn.} 69.6 min β - 1.498 129 I 129 m width unit {syn.} 33.6 D IT β - 0.106 1.604 129 width unit 129 I 130 width unit 33.799 7,9 · 10 20 A β - β - 2.528 130 Xe 131 width unit {syn.} 25 min β - 2.233 131 I 132 width unit {syn.} 3.204 D β - 0.493 132 I
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 1 History 2 occurrences 3 production and representation 4 characteristics of 5 isotopes 6 use 7 biological meaning of 8 safety references 9 proof 10 connections 11 literature 12 Web on the left of

history

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.

occurrence

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
• Nagyagit
• 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.

seems

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.

Tellurium is more intrinsischer more direct Semiconductor with a gap of 0,334 eV

isotopes

¹²⁸ width unit is considered as the isotope with the slowest decay of all not-stable isotopes of all elements.

use

• additive for steel, cast iron, copper and lead alloys, as well as in stainlessHigh-grade steels.
• Curing aid
• semiconductor
• 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
  • a component of optical recording disks (e.g. CD-RW)
  • Memory material in phase the CHANGE random ACCESSMEMORY
• cartridges (blasting caps)
• ceramic(s) production

biological meaning

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)

safety references

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.

proof

connections

• 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]

literature

Web on the left of

• Los Alamos national Laboratory - tellurium
• WebElements.com - tellurium
• EnvironmentalChemistry.com - tellurium