Electron-Diffraction Analysis of Clay Mineral Structures

1 Structures and Structure Modifications of Layer Silicates.- 1. General Introduction to the Structures of Layer and Pseudolayer Silicates.- 2. Some Features of the Structures of Individual Layers.- 3. Use of Structural Polyhedra in the Description and Analysis of Layer Silicate Structures.- 4. Polymorphic and Polytypal Modifications and Repeat Sequence Methods in Layer Silicates.- 5. Regular Structures of Two-Storied Kaolinite-Type Layers.- 6. Regular Structures of Three-Storied Mica-Type Layers.- 7. Regular Structures Made Up of Chlorite Packets.- 2 Experimental Electron-Diffraction Methods of Studying Minerals.- 1. Electron-Diffraction Apparatus.- 2. Preparation of Specimens for Study.- 3. Electron-Diffraction Patterns and Their Analysis.- 3 The Geometrical Theory of Electron Diffraction and Analysis of Clay Mineral Diffraction Patterns.- 1. Theoretical Basis of the Relationship Between the Crystal Lattice and the Diffraction Pattern: The Reciprocal Lattice.- 2. Geometrical Analysis of Electron-Diffraction Patterns.- 3. The Distribution of Reflections on Ellipses on Electron-Diffraction Texture Patterns from Layer Silicates.- 4 The Determination of Intensities in Layer Silicate Diffraction Patterns.- 1. General Comments.- 2. Analysis of Intensities in the Investigation of Layer Silicate Structures.- 3. Wave-Scattering by a Silicate Layer Sequence.- 4. The Distribution of Intensities in Layer Silicate Structure Modifications.- 5. Geometry of Layer Silicate Structural Features, as Revealed Through the Distribution of F or | F | 2.- 6. Effect of Variations in Chemical Composition on the Intensity Distribution in Layer Silicates.- 5 Experimental Electron-Diffraction Studies of Clays and Related Minerals.- 1. The Determination of Crystal Structures.- 2. Uncertainty in theNacrite Structure.- 3. Electron-Diffraction Data on Sepiolite and Palygorskite Structures.- 4. Investigations Using the Microdiffraction Method.- 5. Some Achievements of Electron-Diffraction Studies of Clays, Clay Minerals, and Related Layer Silicates by the Oblique Texture Method.- 6. Possible Fields of Application of the Electron-Diffraction Method in the Study of Minerals Which Are Not Layer Silicates.- Literature Cited.