Summary

These lecture notes present an overview of crystallography, focusing on the hexagonal, trigonal, and cubic systems. Concepts like elements of symmetry and crystallographic elements are discussed.

Full Transcript

Crystallography Prepared by: Dr. wafaa soliman For second year chemistry branch 5- Hexagonal system Elements of symmetry Axis: 7 (1c , 3a1,a2,a3 , 3 (‫ب ينا لمحاور‬ Planes: 7m Center: + ve Crystalographic elements ( a1 = a2 = a3 ≠ c ) ,( α = β = 90 ≠ δ = 120 ) Crystal forms 1- Bas...

Crystallography Prepared by: Dr. wafaa soliman For second year chemistry branch 5- Hexagonal system Elements of symmetry Axis: 7 (1c , 3a1,a2,a3 , 3 (‫ب ينا لمحاور‬ Planes: 7m Center: + ve Crystalographic elements ( a1 = a2 = a3 ≠ c ) ,( α = β = 90 ≠ δ = 120 ) Crystal forms 1- Basal pinacoid..…(0001) 2F 2- Hexagonal prism first order…….(1010) 6F 3- Hexagonal prism second order….(1110) 6F 4- Dihexagonal prism………(hk00) 12F 5- Hexagonal bipyramid first order..(h0hL) 12F 6- Hexagonal bipyramid second order…(hhhL) 12F Crystal forms 7- Dihexagonal bipyramid ……………….…….(hk0L) 24F 6- Trigonal system Elements of symmetry Axis:1∆c ,) 3a1,a2,a3 ) Planes: 3m Center: + ve Crystalographic elements ( a1 = a2 = a3 ≠ c ) ,( α = β = 90 ≠ δ = 120 ) Crystal forms 1- Ditrigonal prism …..(hkw0) 6F 5- Rhombohedron….…….(h0hL) 6F 7- Scalenohedron……………..…… (hkwL) 12F 7- Cubic system Elements of symmetry Axis: ) 3a,b,c , 4▲ ‫(م ع ا لمستويات‬6 ,‫ا ألركان‬ Planes: 9m Center: + ve Crystalographic elements ( a = b = c ),( α = β = δ = 90 ) Crystal forms 1- Cube (hexahedron) ……….(100) 6F 2- Octahedron..……….(111) 8F 3- Rhombododecahedron..……(110)12F 4- Trisoctahedron..….……(hhL) 24F 5- Tetrahexahedron ……………(hk0) 24F 6- Hexaoctahedron…..…………(hkL) 48F

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