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Mineralogical crystallography II.

Class at Faculty of Science |
MG431P64

Syllabus

(i) Types of chemical bonds, lattice energy, atomic and ionic radii, coordination numbers, coordination polyhedra, interstitial sites, deviations from ideal coordination, relationship between structure and morphology.

(ii) General structure rules, Pauling rules (I), structure types, criterions of similarity of the inorganic structures, isomorphism and its factors, polymorphism, polytypism.

(iii) Crystal structures based on closed-packed arrangement, structures with complex anions, symmetrical relationships between crystal structures, homologous and polysomatic series, phase transition in solid-state compounds.

(iv) Chemical composition of minerals, calculations of empirical formulae, defects of crystal structures.

(v) Pauling rules (II), ionic and electrostatic model of crystal structures (short-range/long-range effects, Kirchhoff equations, ionic flux).

(vi) "Bond-valence theory", bond-length vs. bond-strength, basic rules (the valence sum rule, the loop rule and their equivalents in the solid-state physics), importance of bond-valences in mineralgy, validation of crystal structures, stereochemistry of oxysalts and minerals. Lewis acid and Lewis base, their strenghts and relation to the electronegativity. The "valence-matching principle" and its application for studies of minerals and inorganic compounds. Relation between coordination number and the bond-strength.

(vii) Hydrogen bond in solid-state. Basic description, types of coordination of H2O molecules in solid-state, the stability of H-bonds and stability of particular minerals with H-bonds in their structures. Entering of H+ into to nominally anhydrous minerals and it implications. Steric and lattice-induced strain, Jahn-Teller effect, distortion of crystal structures.

(viii) Izomerism, polytypism, polymorphism from the point of view of the bond-valence theroy. Structural hierarchy and categorization of crystal structures.

Annotation

The course will provide an introduction into the structure of minerals and inorganic compounds (the solid state compounds in general). The types of chemical bonds, atomic coordinations, isomorphism, polymorphism and defects of crystal structures will be discussed.

The basic structure types and their derivatives will be presented. An introduction to the bond-valence theory will be made and it will be shown how the theory can be used for description of crystal structures of minerals and inorganic compounds..