Structure of boron nitride nanoscale cones: Ordered stacking of 240 degrees and 300 degrees disclinations

Recently discovered boron nitride (BN) nanoscale cone particles are shown t o consist of an ordered stacking of seamless conical shells. High-resolutio n transmission electron microscopy and nanobeam electron diffraction allowe d the orientation of the BN hexagonal rings to be determined. In all but on e case, the results conformed with a model of orderly stacked 240 degrees d isclinations, which is the smallest cone geometry ensuring the presence of B-N bonds only. One case of a nanoscale cone constituted of 300 degrees dis clinations was found, implying that structures containing line defects of n on-B-N bonds may form.