jMol series chiral nanotube

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 jnanotube applet.
Skip to model five here.