Dehydration of mica (phengite) by electron bombardment in a transmission electron microscope (TEM)

The present paper reports TEM studies on dehydration of natural mica (phengite) by means of electron bombardment in the transmission electron microscope. Dehydration of mica by electron bombardment has been suggested by Nakahira and Uda. An atomic model for the dehydration model is presented, derived from (0001) lattice plane imaging and selected area diffraction patterns. Phengite is a natural mica with strong structural similarity to common muscovite. The phengite crystals investigated have a three-layer trigonal (3T) structure which was confirmed from electron diffraction patterns, X-ray methods, and by polarized light analyses. Experimental details are given. Results are given and discussed. (author)