Iodine
Iodine is a chemical element with symbol I and atomic number 53. The name is from Greek ἰοειδής ioeidēs, meaning violet or purple, due to the color of iodine vapor. Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
36 is the [Kr] core total across four shells.
At a glance
- Atomic number
- 53
- Atomic mass
- 126.904473 u
- Phase
- Solid
- Density
- 4.933 g/cm³
- Melting point
- 386.85 K
- Boiling point
- 457.4 K
- First ionization energy
- 1,008.4 kJ/mol
- Electronegativity
- 2.66
- Electron affinity
- 295.1531 kJ/mol
- Molar heat capacity
- Unavailable
- Period
- 5
- Appearance
- lustrous metallic gray, violet as a gas
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.