Imaging the hydroxyl surface of lizardite at atomic resolution with the atomic force microscope

The [001] surface of lizardite has been examined in air with lhe atomic force microscope (AFM). Images of the hydroxyl gxoups on the outer OH surface of the sheet of octahedra and the tops of the magnesium atoms just below the hydroxyl groups were recorded at atomic resolution. Images of the hexagonal rings of basal oxygen atoms of the sheet of. tetrahedra were recorded at molecular resolution. The images were obtained both from fresh cleavage surfaces prepared immediately prior to examination and from unprepared surfaces of crystals. There was no difference in the results from the two surfaces. The OH surface of lizardite is similar to the outer OH surface of chrysotile asbestos. Recent work on modifying chrysotile asbestos to reduce its chemical reactivity in the environrnent has centered on chemical alteration of the surface of the fibers using POCI3 and organosilicon compounds. The success of the AFM study of lizardite suegests that the AFM can be applied to studies of surface reactions of chrysotile asbestos, as well as to studies of other layer silicates and modulated layer silicates.