Diatomic Molecule
Definition and meaning of Diatomic Molecule in chemistry.
Diatomic describes a molecule made up of exactly two atoms bonded together, whether those atoms are the same element (homonuclear) or different elements (heteronuclear).
In more detail
The bond holding the two atoms together is usually covalent, formed by sharing one or more electron pairs, though some diatomic species (like gas-phase NaCl) are ionic. Seven elements are diatomic in their natural standard state, hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine, a fact chemists must remember when writing and balancing chemical equations, since these elements never appear as lone atoms under normal conditions. Heteronuclear diatomic molecules, such as carbon monoxide and hydrogen chloride, form between two different elements and are typically polar due to differences in electronegativity.
Key facts
| Field | General Chemistry |
|---|---|
| Common formula examples | H2, N2, O2, F2, Cl2, Br2, I2, CO, HCl |
| Homonuclear diatomic elements | 7 (H, N, O, F, Cl, Br, I) |
| Bond type | Usually covalent; occasionally ionic |
Oxygen gas exists naturally as O2, a homonuclear diatomic molecule in which two oxygen atoms share two electron pairs, forming a double covalent bond.
Frequently asked questions
What are the seven diatomic elements?
Hydrogen (H2), nitrogen (N2), oxygen (O2), fluorine (F2), chlorine (Cl2), bromine (Br2), and iodine (I2), these exist as two-atom molecules in their pure, standard state.
Is carbon monoxide a diatomic molecule?
Yes. CO is a heteronuclear diatomic molecule, containing one carbon atom and one oxygen atom joined by a triple bond.