Stable isotope Iodine (I)

Isotope Z(p) N(n) Atomic Mass Natural Abundance Nuclear Spin
I-127 53 74 126.904468 100.00% 5/2+

Properties of Iodine

Name Iodine
Symbol I
Atomic number 53
Atomic weight 126.905
Standard state Solid at 298 °K
CAS Registry ID 7553-56-2
Group in periodic table 17
Group name Halogen
Period in periodic table 5
Block in periodic table p-block
Color Violet-dark gray, lustrous
Classification Non-metallic
Melting point 113.7 °C
Boiling point 184.3 °C
Thermal conductivity 0.449 W/(m·K)
Electrical resistivity > 1015 x 10-8 Ω m
Electronegativity 2.66
Heat of vaporization 20.9 (per mole I atoms) kJ·mol-1
Heat of fusion 7.76 (per mole I atoms) kJ·mol-1
Density of vapor 6.75 g/L
Density of liquid 3.96 g/cm3 at 120 ºC
Density of solid 4.933 g/cm3 at 20 ºC
Electron configuration [Kr]4d105s25p6
Atomic radius 1.33 Å
Ionic (I-) radius 2.20 Å
Common oxidation state -1
Other oxidation states +1, +3, +5, +7
Vapor pressure of solid 0.3075 torr at 25 ºC and 90.5 torr at 113.6 ºC
Critical temperature 545.8 ºC
Critical pressure 48.9 atm
Critical volume 155 cm3/mol