Heteronuclear
Definition and meaning of Heteronuclear in chemistry.
Heteronuclear describes a molecule, bond, or spectroscopic signal that involves atoms of two or more different chemical elements, as opposed to homonuclear, which involves only one element.
In more detail
The term is used most often for diatomic molecules: a heteronuclear diatomic such as CO or HCl has two different atoms joined by a single bond, and because those atoms differ in electronegativity, the bond is polar and the molecule carries a permanent dipole moment. A homonuclear diatomic like O2 or N2, by contrast, has no dipole because both atoms pull on the shared electrons equally. The word also appears in NMR spectroscopy, where "heteronuclear coupling" describes spin-spin interaction between nuclei of different elements or isotopes, such as the proton-carbon coupling exploited in HSQC experiments.
Key facts
| Field | General Chemistry |
|---|---|
| Opposite term | Homonuclear (same element on both sides) |
| Common examples | CO, HCl, NO (heteronuclear diatomics) |
| Spectroscopy use | Heteronuclear coupling/NMR (e.g., 1H-13C in HSQC) |
Carbon monoxide (CO) is a heteronuclear diatomic molecule: its carbon and oxygen atoms have different electronegativities, so the bonding electrons are shared unevenly, giving the molecule a small permanent dipole moment.
Frequently asked questions
What is the difference between heteronuclear and homonuclear molecules?
Heteronuclear molecules contain atoms of two or more different elements, such as HCl, while homonuclear molecules contain atoms of only one element, such as O2 or Cl2.
Why do heteronuclear diatomic molecules have a dipole moment but homonuclear ones do not?
Because the two different atoms in a heteronuclear molecule have different electronegativities, bonding electrons are shared unequally, creating a permanent charge separation; identical atoms in a homonuclear molecule share electrons equally, so there is no net dipole.