Template:Infobox iodine

Iodine,  ₅₃I

General properties
Name, symbol	iodine, I
Appearance	lustrous metallic gray, violet as a gas
Pronunciation	/ˈaɪ.ədaɪn/, /ˈaɪ.ədᵻn/, or /ˈaɪ.ədiːn/ EYE-ə-dyn, EYE-ə-dən, or EYE-ə-deen
Iodine in the periodic table
Br ↑ I ↓ At tellurium ← iodine → xenon
Atomic number (Z)	53
Group, block	group 17 (halogens), p-block
Period	period 5
Element category	diatomic nonmetal
Standard atomic weight (±) (Ar)	126.90447(3)
Electron configuration	[Kr] 4d10 5s2 5p5
per shell	2, 8, 18, 18, 7
Physical properties
Phase	solid
Melting point	386.85 K ​(113.7 °C, ​236.66 °F)
Boiling point	457.4 K ​(184.3 °C, ​363.7 °F)
Density near r.t.	4.933 g/cm3
Triple point	386.65 K, ​12.1 kPa
Critical point	819 K, 11.7 MPa
Heat of fusion	(I2) 15.52 kJ/mol
Heat of vaporization	(I2) 41.57 kJ/mol
Molar heat capacity	(I2) 54.44 J/(mol·K)
vapor pressure (rhombic) P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 260 282 309 342 381 457
Atomic properties
Oxidation states	7, 6, 5, 4, 3, 1, −1 ​(a strongly acidic oxide)
Electronegativity	Pauling scale: 2.66
Ionization energies	1st: 1008.4 kJ/mol 2nd: 1845.9 kJ/mol 3rd: 3180 kJ/mol
Atomic radius	empirical: 140 pm
Covalent radius	139±3 pm
Van der Waals radius	198 pm
Miscellanea
Crystal structure	​orthorhombic
Thermal conductivity	0.449 W/(m·K)
Electrical resistivity	1.3×107 Ω·m (at 0 °C)
Magnetic ordering	diamagnetic
Bulk modulus	7.7 GPa
CAS Number	7553-56-2
History
Discovery and first isolation	Bernard Courtois (1811)
Most stable isotopes of iodine
iso NA half-life DM DE (MeV) DP 123I syn 13 h ε, γ 0.16 123Te 124I syn 4.176 d ε – 124Te 125I syn 59.40 d ε – 125Te 127I 100% – (SF) <29.961 129I trace 1.57×107 y β− 0.194 129Xe 131I syn 8.02070 d β−, γ 0.971 131Xe 135I syn 6.57 h β− – 135Xe
Decay modes in parentheses are predicted, but have not yet been observed

References

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