# Carbon Nanotubes Main design equation for the diameter of the CNT, dependent on the chiral numbers `(n,m)`. $$ d\_{t}=\frac{C\_{h}}{\pi}=\frac{\sqrt{3} a\_{c-c}}{\pi} \sqrt{n^{2}+n m+m^{2}} $$ Would go back to [this site](http://www.photon.t.u-tokyo.ac.jp/~maruyama/kataura/chirality.html) as reference. `a_{c-c}` is the length of the Carbon-Carbon bond, 1.421 Å.