Here is a single-walled (7,3) boron nitride nanotube with intermediate
(neither zig-zag nor arm-chair) chirality. What is it's diameter?
When a 2-wall internally-capped tube model is constructed, we'll compare it
to the image below of a 15-wall nanotube with a 6-wall internal closure:
The above image is tiny part of a much larger image of multi-walled
carbon nanotubes lying like straight sticks of uncooked spaghetti after
falling out of the box into a pot on the stove.
For more nano-tube and nano-cone models, check out Steffen Weber's
Skip to model five here.