Atomic structures and stability of hexagonal BN, diamond and Au multiply-twinned nanoparticles with five-fold symmetry

The atomic structures and stability of hexagonal-BN, diamond and Au nanopar ticles with a five-fold symmetry were investigated by high-resolution elect ron microscopy, electron diffraction and molecular orbital calculations. Di amond, Au and BN have {111}, {111} and {112} twin planes, and [110], [110] and [201] five-fold axes, respectively. The sizes for diamond, BN and Au we re 5 mum, and 300 and 10 nm, respectively, and many stacking faults and dis locations were observed between the twin boundaries in diamond particles. B N has quite a smaller distortion compared to diamond and Au, which was also shown by molecular orbital and molecular mechanics calculations. (C) 2001 Elsevier Science B.V. All rights reserved.