Palladium

of the titles of this article is ambiguous. For further meanings see palladium (term clarifying).
Characteristics
rhodium - palladium - silver
never
Pd
Pt

[Kr] 4d 10 5s 0
60
46
Pd

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generally
name, symbol, ordinal number palladium, Pd, 46
series of transition metals
group, period, block 10, 5, D
appearance silvery, knows, metallically
proportion at the Earth's shell 1 · 10 -6 %
atomically
atomic mass 106,42
Atomic radius (computed) 140 (169) pm
Kovalenter radius 131 pm
van the Waals radius 163 pm
Elektronenkonfiguration [Kr] 4d 10 5s 0
electrons per energy level 2, 8, 18, 18, 0
1. Ionization energy 804.4 kJ/mol
2. Ionization energy 1870 kJ/mol
3. Ionization energy 3177 kJ/mol
physically
state of aggregation firmly
crystal structure cubically face-centered
density (Mohshärte) 12023 kg/m 3 (4,75)
magnetism -
melting point 1828.05 K (1554.90 °C)
boiling point 3236 K (3125 °C)
molecular volume 8,56 · 10 -6 m 3 /mol
heat of vaporization 357 kJ/mol
heat of fusion 17.6 kJ/mol
steam pressure 1.33 Pa at 1825 K
speed of sound 3070 m/s with 293,15 K
specific thermal capacity 244 j (kg · K)
Electrical conductivity 9,5 · 10 6 S /m
heat conductivity 71.8 w (m · K)
Chemically
oxidation conditions 0, +2, +4
oxides (basicity) PdO (easily basic)
Elektronegativität 2.20 (Pauling scale)
Normalpotenzial 0.915 V (Pd 2+ + 2e - → Pd)
isotopes
isotope NH t 1/2 ZM CPU M eV ZP
100 Pd {syn.} 3.63 D ε 0.363 100 RH
101 Pd {syn.} 8.47 h ε 1.980 101 RH
102 Pd 1.02% Pd 103 Pd are stable {
syn. with 56 neutrons} 16.991 D ε 0.543 103 RH
104 Pd 11.14% Pd is stably also58 neutrons
105 Pd 22.33% Pd 106 Pd 27.33% Pd are
stable are stably with 60 neutrons 107 Pd {
syn. with 59 neutrons} 6,5 · 10 6 A β - 0.033 107 AG
108 Pd 26.46% Pd109 Pd are stable {
syn. with 62 neutrons} 13.7012 h β - 1.116 109 AG
110 Pd 11.72% Pd 111 Pd are stable {
syn. with 64 neutrons} 23.4 min β - 2.190 111 AG
112 Pd {syn.} 21.03 h β - 0.288 112 AG
NMR characteristics
105 Pd
nuclear spin 5/2
gamma/ wheel/T 1,224 · 10 7
sensitivity 0.00112
Larmorfrequenz with B = 4.7 T 9.15 M cycles per second
as far as possible and common, is used SI-UNITs.
If not differentlynoted,
the indicated data apply with standard conditions.

Palladium is a chemical element in the periodic system of the elements with the symbol Pd and the ordinal number 46. The rare silver-white transition metal of group of platinum resembles very platinum in the chemical behavior.

Table of contents

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history

palladium was discovered 1803 by William Hyde Wollaston. It designated it two years before 1804 after that discovered Asteroiden Pallas. Wollaston found the element 46in South American platinum ore due to to small yields samples dissolved at platinum out in aquae regiae.

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occurrences

metallic palladium and palladiumhaltige alloys in river soaps are in the Urals, Australia, Ethiopia and in north and South America. Itare however exploited for decades as far as possible.

Today it is won usually from nickel - and Kupfererzen. More than 50% originate from Russian promotion.

With the old car disposal the portion of the rezyklierten palladium from the waste gas catalysts will rise. Over the possibilityto the production of palladium from burned down fuel elements, see precious metal synthesis.

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characteristics

Palladium, 99,99% rein
palladium, 99.99% palladium

a metal and the lightest element of group of platinum are pure. Therefore it has the lowest melting point from the elements of this group and is also most reaction-joyfully. At ambient temperature it does not react however with oxygen. It keeps its metallic gloss at air and does not start not. In the glowed condition it is soft and duktil, during deformation at low temperatures rises the firmness and hardness howeverfast on (cold working).

Palladium is a precious metal, even if it is clearly more reactive than relatives the element platinum: It separates in nitric acid. In hydrochloric acid it dissolves with Luftzutritt slowly. The precious metal character from palladium is thatthe neighbouring silver comparably: In many acids palladium is the nobler metal, in hydrochloric acid behaves it however due to the formation of easy-soluble palladium chloride connections more unedler.

Palladium possesses the highest absorption capacity of all elements for hydrogen. At ambient temperature it can do that900-fache, Palladiummohr the 1200-fache and colloidal palladium solutions the 3000-fache of the own volume bind. One can describe the absorption of hydrogen as release from hydrogen in the metal lattice and as formation palladium of a hydride with the approximate composition Pd 2 H. With 30 °Cand normal print corresponds the maximum hydrogen palladium relationship to the formula PdH 0.608.

Usually it accepts the Oxidationsstufen +2 and +4. With connections of the apparent Oxidationsstufe +3 it concerns Pd (II) /Pd (IV) - alloys. In newer investigations also hexavalent palladium could be represented.

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use

finely divided is palladium a exzellenter catalyst for the acceleration of chemical reactions, in particular hydrogenations and dehydrogenations (installation and withdrawal of hydrogen), as well as to the Cracken of hydrocarbons.

Further applications:

  • Waste gas catalysts for petrol engines. (Palladium displaces the more expensive Platinum.)
  • decoration goods (particularly in China)
  • weissgold (palladium “decolorizes” gold)
  • platinum crucible (80% Pt, 20% Pd)
  • purifying foils. Similar to the gold foil palladium can be rolled out to 0.00001 mm of thin foils.
  • Cleaning of hydrogen. In hot palladium hydrogen possesses inhigh Diffusionsvermögen.
  • Contact materials for interphones
  • of tooth implants
  • medical instruments
  • of electrode materials for spark plugs (aviation)
  • Pd/Ni alloys as replacement for gold in the electrical industry
  • nano-technology (over e.g. serves as catalyst. to manufacture molecular connections)
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