An Electron Microscope and Electron Diffraction Study of Fine Manganese Particles Prepared by Evaporation in Argon at Low Pressures

Abstract

Fine manganese particles prepared by evaporation in argon, or in xenon, at low pressures were studied mainly by electron microscopy and electron diffraction. The particles showed clear-cut crystal habits and they were classified into three types; firstly, particles of the shape of a tristetrahedron bounded by twelve {211}-planes, the crystal structure of which was α-man-ganese; secondly, particles of the shape of a rhombic dodecahedron bounded by twelve {110}-planes, the crystal structure of which was β-manganese, thirdly particles of the shape of a needle-like rod, the crystal structure of which is still unknown. Extra spots {00 l }, (\(l{\backslash\llap{=}}4n\)), observed in the selected area diffraction pattern from a β-manganese particle are explained by dynamical double reflections.