title: Crystal lattice imaging of the silica and alumina faces of kaolinite using atomic force microscopy.
abstract: The crystal lattice images of the two faces of kaolinite (the silica face and the alumina face) have been obtained using contact-mode atomic force microscopy (AFM) under ambient conditions. Lattice resolution images reveal the hexagonal surface lattice of these two faces of kaolinite. Analysis of the silica face of kaolinite showed that the hexagonal surface lattice ring of oxygen atoms had a periodicity of 0.50±0.04nm between neighboring oxygen atoms, which is in good agreement with the surface lattice structure of the mica basal plane. The center of the hexagonal ring of oxygen atoms is vacant. Analysis of the alumina face of kaolinite showed that the hexagonal surface lattice ring of hydroxyls surround a hydroxyl in the center of the ring. The atomic spacing between neighboring hydroxyls was determined as 0.36±0.04nm. Ordering of the kaolinite particles for examination of the silica and alumina surfaces was accomplished using different substrates, a procedure previously established. Crystal lattice imaging supports previous results and independently confirms that the two faces of kaolinite have been properly identified.
authors.affiliation: Department of Metallurgical Engineering, College of Mines and Earth Sciences, University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112, USA.
authors.forename: Vishal
authors.initials: V
authors.lastname: Gupta
authors.forename: Marc A
authors.initials: MA
authors.lastname: Hampton
authors.forename: Anh V
authors.initials: AV
authors.lastname: Nguyen
authors.forename: Jan D
authors.initials: JD
authors.lastname: Miller
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D003460:Crystallization; D007616:Kaolin / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D007616:Kaolin; D012822:Silicon Dioxide; D000537:Aluminum Oxide; D010100:Oxygen