![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Molecule_HOMO-LUMO_diagram.svg/640px-Molecule_HOMO-LUMO_diagram.svg.png&w=640&q=50)
HOMO and LUMO
Highest occupied and lowest unoccupied molecular orbitals / From Wikipedia, the free encyclopedia
"HOMO" redirects here. For other uses, see Homo (disambiguation).
In chemistry, HOMO and LUMO are types of molecular orbitals. The acronyms stand for highest occupied molecular orbital and lowest unoccupied molecular orbital, respectively. HOMO and LUMO are sometimes collectively called the frontier orbitals, such as in the frontier molecular orbital theory.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Molecule_HOMO-LUMO_diagram.svg/320px-Molecule_HOMO-LUMO_diagram.svg.png)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/CO2_HOMO.gif/320px-CO2_HOMO.gif)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/3/38/CO2_LUMO.gif/320px-CO2_LUMO.gif)