What is a boron nitride nanotube?

Take a single sheet of hexagonal boron nitride — "white graphene" — and roll it into a seamless cylinder. The result is a boron nitride nanotube: the same honeycomb lattice and tubular geometry as a carbon nanotube, but with carbon's atoms replaced, alternating, by boron and nitrogen.

One substitution, a different material

In a carbon nanotube every lattice site is identical carbon, and the bonds are non-polar. In a BNNT the lattice alternates between boron (electron-poor) and nitrogen (electron-rich). The B–N bond is partially ionic, and that polarity is the root of nearly every property that distinguishes BNNT from its carbon cousin: its exceptional thermal and chemical stability, its constant wide electronic band gap, and its piezoelectricity.

The defining contrast. A carbon nanotube is a conductor or a semiconductor depending on exactly how the sheet is rolled (its "chirality"). A boron nitride nanotube is an electrical insulator with a band gap of about 5.5 electron-volts regardless of how it is rolled. Its electronic behaviour is decided by chemistry, not geometry — a fact with deep consequences both for applications and for manufacturing. See the full BNNT-vs-CNT comparison →

A short history

Year	Milestone
1994	Theory predicts that a hexagonal-BN tube would be a wide-gap insulator with a chirality-independent band gap, before any had been made.
1995	The first BNNTs are synthesised by arc discharge — the founding experimental paper.
1996	Tubes with fewer walls produced; high-pressure laser routes demonstrated.
1999	Ball-milling-and-annealing opens a mechanochemical, potentially scalable route.
2002–2009	Chemical-vapour-deposition chemistries mature; the pressurised vapor/condenser (PVC) route enables higher-quality tubes.
2014	Induction thermal plasma demonstrated at pilot scale — the first credible path to kilogram quantities.
2024–2026	Mineral feedstocks, catalyst chemistry, and nucleation control sharpen the cost and quality frontier.

Every milestone above is linked to its primary source in the reference library, and laid out in full on the timeline.

Where the terms come from

h-BN hexagonal boron nitride, the flat sheet form. BNNT the rolled tube. chirality the angle at which the sheet is rolled. few-walled tubes made of one to a few concentric cylinders — generally the most desirable. wall count and diameter the two structural knobs that set a tube's quality and price.

BNNT is one member of a larger boron nitride family that also includes flat nanosheets and superhard cubic boron nitride.

Next: why these properties matter →