Cadmium

characteristics
silver - cadmium - Indium
Zn
CD
Hg

[Kr] 4d 10 5s 2
64
48
CD

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generally
name, symbol, ordinal number cadmium, CD, 48
series Transition metals
group, period, block 12, 5, D
appearance silvery grey metallically
proportion at the Earth's shell 3 · 10 -5 %
atomically
atomic mass 112.411
atomic radius (computed) 155 (161) pm
Kovalenter radius 148 pm
van the Waals radius 158 pm
Elektronenkonfiguration [Kr] 4d 10 5 s 2
electrons per energy level 2, 8, 18, 18, 2
electron affinity 4.07 eV
1. Ionization energy 867.8 kJ/mol
2. Ionization energy 1631.4 kJ/mol
3. Ionization energy 3616 kJ/mol
physically
state of aggregation firmly
crystal structure hexagonally
density (Mohshärte) 8650 kg/m 3 (2)
magnetism -
melting point 594.22 K (321.07 ° C)
boiling point 1040 K (767 °C)
molecular volume 13,00 · 10 -6 m 3 /mol
heat of vaporization 100 kJ/mol
heat of fusion 6.192 kJ/mol
steam pressure 14.8 Pa with 597K
speed of sound 2310 m/s with 293,15 K
specific thermal capacity 233 j (kg · K)
Electrical conductivity 13,8 · 10 6 S /m
heat conductivity 96.8 w (m · K)
Chemically
oxidation conditions of 2
oxides (basicity) CdO (easily basic)
normal potential -0.403 V (CD 2+ + 2e - → CD)
Elektronegativität 1.69 (Pauling scale)
isotopes
isotope NH t 1/2 ZM CPU M eV ZP
104 CD {syn.} 57.7 min ε 1.137 104 AG
105 CD {syn.} 55.5 min ε 2.739 105 AG
106 CD 1.25% CD 107 CD are stable {
syn. with 58 neutrons} 6.50 h ε 1.417 107 AG
108 CD 0.89% CD 109 CD are stable {
syn. with 60 neutrons} 462.6 D ε 0.214 109 AG
110 CD 12.49% CD is stably with 62 neutrons
111 CD 12.8% CD is stably with 63 neutrons
112 CD 24.13% CD is stably with 64 neutrons
113 CD 12.22% 7,7 · 10 15 A β - 0,316 113 in
113 m CD {syn.} 14.1 A β -
IT
0.580
0.264
113 in
113 CD
114 CD 28.73% CD is stably with 66 neutrons
115 CD {syn.} 53.46 h β - 1.446 115 in
115 m CD {syn.} 44.6 D β -
IT
1.627
0.181
115 in
115 CD
116 CD 7.49% CD is stably with 68 neutrons
117 CD {syn.} 2.49 h β - 2.516 117 in
118 CD {syn.} 50.3 min β - 0,520 118 in
NMR characteristics
111 CD 113 CD
nuclear spin 1/2 1/2
gamma/ wheel/T 5,673 · 10 7 5,934 · 10 7
sensitivity 0.00954 0.0109
Larmorfrequenz with B = 4.7 T 42.4 M cycles per second of 44.4 M cycles per second
as far as possibleand common, SI-UNITs are used.
If not differently notes,
the indicated data apply with standard conditions.

Cadmium (also cadmium; cadmea (lat.) = kadmía (griech.) = Zinkerz) a chemical element is in the periodic system of the elements with the symbol CD and that Ordinal number 48.

Table of contents

history

1817 Friedrich Stromeyer and Carl Samuel Hermann discovered independently cadmium (Latin cadmia, Greek kadmeia for Galmei) in contaminated zinc carbonate. Approximately 100 years the metal was won only in Germany. Strohmeyer noticed that itselfcontaminated zinc carbonate with heating up discoloured: a behavior, which did not show pure zinc carbonate.
Because of its Giftigkeit that registered British Pharmaceutical Codex of 1907 cadmium iodide as means for the treatment of swollen joints (enlarged joints), skrofulösen glands (scrofulous glands) and frost boils (chilblains).

ThoseInternationally Conference on Weights and Measures defined 1927 the length of a meter as the 1.553.164, 13-fache wavelength of a red spectral line of the cadmium. This definition was maintained to 1960.

occurrences

Cadmiumhaltige of ores are rare. Greenockit (CdS) is nearlyalways with Sphalerit (ZnS) verschwistert. Cadmium is won therefore as by-product during the zinc smelting, to small extent also during the lead and Kupferverhüttung. Smaller quantities result also with the recycling of iron and steel.

The reduction to the metallic cadmium takes placeby

characteristics

cadmium is a soft, hämmerbares, duktiles, blue-white metal. In chemical compounds it is present usually bivalent. Chemically it resembles the zinc, it is inclined however rather to the educationof complex connections with the Koordiationszahl 4. Cadmium is steady at air, in the warmth forms it an oxide film. In the heat it burns with more reddish to yellow flame to cadmium oxide CdO (poisonous!).

hochreiner Cadmium-Draht
highly pure cadmium wire

use

  • rust protection forFerrous metals (Vercadmen)
  • nickel cadmium Akkus
  • of Farbpigmente (fire-brigade red and post office yellow (CdS)) for colors and plastics (meanwhile small practice meaning because of possible health endangerment)
  • alloy metal in lowmelting alloys, for example bearing materials or Wood metal
  • lubricant in disc brakes
  • a component of soldering materials (tin solder), also for brazing metals
  • Production of semiconductors
  • cadmium oxide as phosphors in black-and-white TV picture tubes as well as additive in blue and green phosphorus of color tubes.
  • Control rods in the nuclear technology
  • use in exposure meters, since spectral sensitivity resembles that of the human eye.
  • Cadmiumtellurid as infrared-sensitive sensor for cameras (focal planarray)
  • in solar cells (Cadmiumtellurid) to the generation of current
  • CD-Stearat as stabilizer in plastics for example in PVC (insensitive to light)
  • Weston standard cell
  • cadmium bismuth alloys for fuses
  • silver cadmium alloys as deoxidizers in the production of Sterling silver
  • decoration goods: gold-green gold cadmium alloys
  • cadmium lamp
  • in the electrical physiology become cadmium ionsfor the blockade of tension-activated calcium channels uses.

proof

as proof reaction for cadmium cations is considered the precipitation with sulfide - to solution or Schwefelwasserstoff-Wasser as yellow cadmium sulfide. Other heavy metal ions disturb this proof, so that a cation separation course is to be accomplished before.

Connections

safety references

cadmium and its connections are high malicious and probably krebserregend.
Inhaled one cadmiumhaltiger dust leads to damage to lung, liver and kidney. See Gressenicher illness and Itai Itai illness.
InWork areas, in which with cadmium connections heated up (soldering places and cadmium plating baths), one works is to be provided for a good aeration or exhaust.

Cadmium is one of the few elements without a biological function in the human body. Cadmium-deaf can work however like a pregnancy hormone.In accordance with chemical prohibition regulation the cadmium content in plastics may not exceed 0.01 Gewichts% (100 mg/kg). This limit value applies European Union far.

health effects with incorporation into the human body

cadmium is in the chemical industry an unavoidable by-product that zinc -, Lead - and Kupfergewinnung. Also in fertilizers and Pestiziden cadmium is to be found.

admission and driving

main are taken up cadmium by humans by the food. The bio accumulation in the body is substantially increased thereby. To the cadmium-richFood count: Liver, mushrooms, Schellfi, shells, cocoa powders and dried sea-grass. Besides it comes since the introduction from artificial fertilizers to an enrichment of cadmium on agricultural surfaces and thus in almost all food. Cadmium is naturally contained as pollution in phosphate ores.By the world-wide shortage of the raw material phosphate increasingly more strongly cadmiumhaltige occurrences are exploited. Contrary to applying of sewage sludge there is no legal maximum value for cadmium for applying of artificial fertilizers. In addition, tobacco smoke transports large cadmium quantities into the lungs,of where out it with the blood in the body distributes.

Particularly persons, who work in factories with high cadmium output, are exposed to increased dangers. In addition, of “wild” garbage places and metal works dangers go out. The inhalation of cadmium knows the lungsseriously damage and even to death lead. Accidents in the industry as in the Chinese province Guangdong make the material dangers clear.

procedure in the human body

cadmium is transported by the blood first to the liver, where itwith proteins to complexes connects itself, which are continued to transport to it to the kidneys. In the liver it induces the synthesis of Metallothioneinen, which can already bind and to the elimination bring the remaining cadmium in such a way in the intestine. In the kidneyscadmium collects itself. Separating is actually caused by handicap and destruction of the normal kidney function essential proteins and coal hydrates. It needs for a very long time, until the cadmium, which stored itself into the kidneys, can be separated again. (see bio accumulation)

damage and symptoms

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