A Study of the Cleaved Surfaces of Phyllosilicates (Brucite and Chlorite) Using AFM and LEED

Abstract

Following talc, phlogopite and muscovite, which were reported in a previous report (J. Surface Sci. Soc. Jpn.17, pp.90-97, 1996), the cleavage surfaces of brucite and chlorite (clinochlore) are studied using AFM and LEED. The (0001) surface of natural brucite crystal cleaved in a pure argon atmosphere was placed in an AFM sample chamber with an argon gas stream. A hexagonal network image of OH^- ions with a distance of 3.1Å was clearly observed. This structure was supported by the observed LEED pattern and crystallographical data. For the cleavage surface of chlorite in a pure argon atmosphere, two types (i.e. talc-like AFM image (O^2--O^2- distance of 2.5 Å) and brucite-like AFM image (OH^--OH^- distance of 2.7 Å)) were observed. However, the lattice distances from these AFM images were shorter than those from the AFM images of talc and brucite, respectively. A large-scale (1000 nm x 1000 nm) AFM image of the chlorite cleavage surface indicates that there are island-shaped Brucite-like layers existing on basal talc-like layer. The interpretation of this AFM image is supported by the observed chlorite LEED pattern, which consists of diffraction spots of talc-like and brucite-like structures.