![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Cycloparaphenylene_3D_Model.stl/640px-Cycloparaphenylene_3D_Model.stl.png&w=640&q=50)
Cycloparaphenylene
From Wikipedia, the free encyclopedia
A cycloparaphenylene is a molecule that consists of several benzene rings connected by covalent bonds in the para positions to form a hoop- or necklace-like structure. Its chemical formula is [C6H4]n or C
6nH
4n Such a molecule is usually denoted [n]CPP where n is the number of benzene rings.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/CNT_CPP.png/640px-CNT_CPP.png)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Cycloparaphenylene_3D_Model.stl/640px-Cycloparaphenylene_3D_Model.stl.png)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Cycloparaphenylene-3D-spacefill.png/640px-Cycloparaphenylene-3D-spacefill.png)
A cycloparaphenylene can be considered as the smallest possible armchair carbon nanotube, and is a type of carbon nanohoop.[2] Cycloparaphenylenes are challenging targets for chemical synthesis due to the ring strain incurred from forcing benzene rings out of planarity.