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AA _h BN crystal, basic structure of boron nitride nanotubes.

ABSTRACT: AA _h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm2₁), is reported here. This new AA _h BN crystal exhibits a 'linear' morphology for high-resolution transmission electron microscopy (HRTEM) and a (non-hexagonal) 'diagonal' electron-diffraction pattern, which have been experimentally demonstrated in this article. It is also demonstrated that this new crystal is the basic structure of multi-walled BN nanotubes (BNNTs) existing in the form of a helix. The helical AA _h BNNTs exist in a metastable phase owing to 〈200〉 texture growth of the orthorhombic crystal, where the energy is ∼15 meV higher than that of stable AB or AA' BN. It is shown that the typical scanning electron microscope 'fluffy cotton-like' morphology of BNNTs is due to secondary growth of diverse BN sheets (including mono-layers) on incoherently scrolled wall strands of BNNTs, providing further evidence for the helical structure with HRTEM evidence for a left-handed helix.

SUBMITTER: Lee JK

PROVIDER: S-EPMC8562660 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature

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AA h BN crystal, basic structure of boron nitride nanotubes.

Lee Jae-Kap JK Kim Jin-Gyu JG Yu Seunggun S Lee Sang-Gil SG Kim Yesong Y Moon Dong Ju DJ

IUCrJ 20211016 Pt 6

AA h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm21), is reported here. This new AA h BN crystal exhibits a 'linear' morphology for high-resolution transmission electron microscopy (HRTEM) and a (non-hexagonal) 'diagonal' electron-diffraction pattern, which have been experimentally demonstrated in this article. It is also demonstrated that this new crystal is the basic structure of multi-walled ...[more]

PMID: 34804553

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