Diatomic: definition in chemistry
Diatomic: Made of two atoms. Hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine exist as diatomic molecules: H₂, N₂, O₂, F₂, Cl₂, Br₂ and I₂.
These seven elements bond to themselves in pairs because two atoms sharing electrons are more stable than single atoms. A common memory aid is HOFBrINCl, pronounced hoff-brinkle. Compounds can be diatomic too, such as carbon monoxide (CO) and hydrogen chloride (HCl).
Examples
- Oxygen (O₂) — two atoms joined by a double bond
- Nitrogen (N₂) — a very strong triple bond
- Chlorine (Cl₂) — a yellow-green gas
- Carbon monoxide (CO) — a diatomic compound
On the periodic table
Six of the seven diatomic elements form a 7 shape on the table, starting at nitrogen (element 7), running across to fluorine and down the halogens; hydrogen sits apart.