Answer
See work below for details.
Work Step by Step
1. Boron nitride contains BN units that are isoelectronic (having the same number of electrons) with carbon in the sense that each BN unit contains eight valence electrons, or four per atom (just like carbon).
2. The size and electronegativity of a carbon atom are also almost equal to the average of those properties for a boron atom and a nitrogen atom.
Because of this, BN forms a number of structures that are similar to those formed by carbon, including nanotubes.
