A comprehensive NMR study of cubic and hexagonal boron nitride

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Boron nitride (BN) exists in various crystalline forms, including cubic and hexagonal.
• Accurate characterization of BN materials is crucial for understanding their properties and applications.
• Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for probing atomic nuclei.

Purpose of the Study:

• To develop and demonstrate comprehensive NMR techniques for characterizing cubic and hexagonal boron nitride.
• To obtain precise chemical shift and quadrupole coupling parameters for boron and nitrogen nuclei.
• To explore the applicability of these NMR methods to related materials.

Main Methods:

• Utilized a variety of NMR techniques and measurements on all accessible nuclei.
• Employed 11B to 15N cross-polarization under magic angle sample spinning (MASS) conditions.
• Performed measurements at natural isotope abundance for hexagonal boron nitride.

Main Results:

• Achieved a complete and precise set of chemical shift and quadrupole coupling parameters for boron and nitrogen in both cubic and hexagonal boron nitride.
• Successfully demonstrated 11B to 15N cross-polarization for hexagonal boron nitride at natural abundance.
• Validated the NMR approach for crystalline boron nitrides.

Conclusions:

• The presented NMR approach offers a robust method for detailed characterization of boron nitride materials.
• The methodology is extendable to structurally related materials such as composites, nanotubes, and amorphous ceramics.
• Precise NMR parameters enhance the understanding of bonding and local environments in boron nitride systems.