de en fr hr it es
Neighborhood
Se
34
Br
35
Kr
36
Te
52
I
53
Xe
54
Po
84
At
85
Rn
86

 

Periodic table

de  German

Iod

en  English

Iodine

fr  French

Iode

hr  Croatian

Jod

it  Italian

Iodio

es  Spanish

Yodo

 

I
I
Iodum

PERIODIC TABLE OF THE ELEMENTS

IODINE

HALOGENS ELEMENT

 

Atomic number:53

Group numbers:17

Period:5

Electronic configuration:[Kr] 4d10 5s2 5p5

Formal oxidation number:-1 +1 +5 +7

Electronegativities:2.66

Atomic radius / pm:133.1

Relative atomic mass:126.90447 ± 0.00003

 

Iodine was discovered by Bernard Courtois (FR) in 1811. The origin of the name comes from the Greek word iodes meaning violet. It is a shiny, black, non-metallic solid with characteristic odour. It sublimes easily and as a gas it is violet and intensely irritating to the eyes, nose and throat. Iodine occurs on land and in the sea in sodium and potassium compounds. It is required in small amounts by humans. Iodine was once used as an antiseptic, but no longer due to its poisonous nature.

PHYSICAL PROPERTIES

Density / g dm-3:4930 (293 K)

Molar volume / cm3mol-1:25.74 (293 K)

Electrical resistivity / μΩcm:1.3E+15 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:0.449

Melting point / °C:113.7

Boiling point / °C:184.4

Heat of fusion / kJ mol-1:15.27

Heat of vaporization / kJ mol-1:41.67

Heat of atomization / kJ mol-1:107.24

IONIZATION ENERGIES

First ionization energy / kJ mol-1:1008.40

Second ionization energy / kJ mol-1:1845.90

Third ionization energy / kJ mol-1:3184.04

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:0.5

in the oceans / ppm:0.05

CRYSTALLOGRAPHIC DATA

base-centered orthorhombic

Crystal structure:

base-centered orthorhombic

Unit-cell dimensions / pm:

a=726.47, b=478.57, c=979.08

Space group:

Cmca

ISOTOPES

IsotopeRelative atomic massMass percent (%)
127I126.904468(4)100

REDUCTION POTENTIALS

Balanced half-reaction Eo / V
I2(s) + 2e- = 2I-+0.535
I2(aq) + 2e- = 2I-+0.615
3I2 + 2e- = 2I3-+0.789
I3- + 2e- = 3I-+0.536
H5IO6 + H+ + 2e- = IO3- + 3H2O+1.601
HIO52- + 3H+ + 2e- = IO3- + 2H2O+1.898
HIO52- + 8H+ + 6e- = HIO + 4H2O+1.389
2HIO52- + 18H+ + 14e- = I2(s) + 10H2O+1.384
3HIO52- + 27H+ + 22e- = I3- + 15H2O+1.357
HIO52- + 9H+ + 8e- = I- + 5H2O+1.288
HIO4 + 2H+ + 2e- = HIO3 + H2O+1.626
IO4- + 2H+ + 2e- = IO3- + H2O+1.653
HIO4 + 6H+ + 6e- = HIO + 3H2O+1.290
IO4- + 7H+ + 6e- = HIO + 3H2O+1.235
2HIO4 + 14H+ + 14e- = I2(s) + 8H2O+1.300
3HIO4 + 21H+ + 22e- = I3- + 12H2O+1.276
HIO4 + 7H+ + 8e- = I- + 4H2O+1.215
IO3- + 6H+ + 4e- = I+ + 3H2O+1.155
IO3- + 4H+ + 4e- = IO- + 2H2O+0.972
2IO3- + 12H+ + 10e- = I2(s) + 6H2O+1.196
2IO3- + 12H+ + 10e- = I2(aq) + 6H2O+1.178
IO3- + 2Cl- + 6H+ + 4e- = ICl2- + 3H2O+1.24
2HIO3 + 10H+ + 10e- = I2(s) + 6H2O+1.169
3HIO3 + 15H+ + 16e- = I3- + 9H2O+1.145
HIO3 + 5H+ + 6e- = I- + 3H2O+1.078
2HIO + 2H+ + 2e- = I2(s) + 2H2O+1.354
2IO- + 4H+ + 2e- = I2(s) + 2H2O+2.005
3HIO + 3H+ + 4e- = I3- + 3H2O+1.213
3IO- + 6H+ + 4e- = I3- + 3H2O+1.701
IO- + 2H+ + 2e- = I- + H2O+1.313
HIO + H+ + 2e- = I- + H2O+0.987
2ICl3(s) + 6e- = I2(s) + 6Cl-+1.28
2ICl(s) + 2e- = I2(s) + 2Cl-+1.22
2ICl + 2e- = I2(s) + 2Cl-+1.19
2ICl2- + 2e- = I2(s) + 4Cl-+1.056
2IBr(aq) + 2e- = I2(s) + 2Br-+1.02

 

52 Tellurium <=
53 Iodine
 => 54 Xenon