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29
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30
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31
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47
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48
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49
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79
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80
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81

 

Periodic table

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Kadmium

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Cadmium

fr  French

Cadmium

hr  Croatian

Kadmij

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Cadmio

es  Spanish

Cadmio

 

Cd
Cd
Cadmium

PERIODIC TABLE OF THE ELEMENTS

CADMIUM

TRANSITION ELEMENT:
ZINC GROUP

 

Atomic number:48

Group numbers:12

Period:5

Electronic configuration:[Kr] 4d10 5s2

Formal oxidation number:+2

Electronegativities:1.69

Atomic radius / pm:148.9

Relative atomic mass:112.411 ± 0.008

 

Cadmium was discovered by Friedrich Strohmeyer (DE) in 1817. The origin of the name comes from the Latin word cadmia meaning calamine (zinc carbonate, ZnCO3), or from the Greek word kadmeia with the same meaning. It is a soft, malleable, blue-white metal that tarnishes in air, soluble in acids, insoluble in alkalis. Boiling cadmium gives off a weird, yellow-coloured vapour that is poisonous. Cadmium can cause a variety of health problems, including kidney failure and high blood pressure. Cadmium is obtained as a by product of zinc refining. The mayor use of cadmium is in electroplating of steel to protect it from corrosion. It is also used to make nickel-cadmium batteries. The ability of cadmium to adsorb neutrons has made it of great importance in the design of nuclear reactors. Its compounds are found in paint pigments and a wide variety of intense colours.

PHYSICAL PROPERTIES

Density / g dm-3:8650 (293 K)

 7996 (m.p.)

Molar volume / cm3mol-1:13.00 (293 K)

 14.06 (m.p.)

Electrical resistivity / μΩcm:6.83 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:96.8

Melting point / °C:312.07

Boiling point / °C:767

Heat of fusion / kJ mol-1:6.11

Heat of vaporization / kJ mol-1:100

Heat of atomization / kJ mol-1:112.05

IONIZATION ENERGIES

First ionization energy / kJ mol-1:867.78

Second ionization energy / kJ mol-1:1631.42

Third ionization energy / kJ mol-1:3616.30

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:0.098

in the oceans / ppm:0.0001

CRYSTALLOGRAPHIC DATA

hexagonal

Crystal structure:

hexagonal

Unit-cell dimensions / pm:

a=297.94, c=561.86

Space group:

P63/mmc

ISOTOPES

IsotopeRelative atomic massMass percent (%)
106Cd105.906458(6)1.25(4)
108Cd107.904183(6)0.89(2)
110Cd109.903006(3)12.49(12)
111Cd110.904182(3)12.80(8)
112Cd111.902757(3)24.13(14)
113Cd112.904401(3)12.22(8)
114Cd113.903358(3)28.73(28)
116Cd115.904755(3)7.49(12)

REDUCTION POTENTIALS

Balanced half-reaction Eo / V
Cd2+ + 2e- = Cd(s)- 0.403
Cd(CN)42- + 2e- = Cd(s) + 4CN-- 1.09
Cd(NH3)42+ + 2e- = Cd(s) + 4NH3- 0.61
Cd(OH)2(s) + 2e- = Cd(s) + 2OH-- 0.81
CdS(s) + 2e- = Cd(s) + S2-- 1.17

 

47 Silver <=
48 Cadmium
 => 49 Indium