x射線衍射課件 第1章 x射線晶體學(xué)基礎(chǔ)-文庫吧
2024-12-30 08:19 本頁面
【正文】 ? 對(duì) 稱 性： 晶體的理想外形和晶體內(nèi)部結(jié)構(gòu)都具有特定的對(duì)稱性。 1. 晶體具有如下性質(zhì)： 剛玉 鄰苯二甲酸氫 鍺酸鉍 電氣石 2. 晶體結(jié)構(gòu)與空間點(diǎn)陣 A（術(shù)語回顧） ? 晶體 (crystal) It is arrangement of atoms in the crystal is periodic. ? 點(diǎn)陣 （ Lattice） An infinite array of points in space, in which each point has identical surroundings to all others. ? 晶體結(jié)構(gòu) （ Crystal Structure） It can be described by associating each lattice point with a group of atoms called the MOTIF (BASIS) ? 單位晶胞（ Unit Cell） The smallest ponent of the crystal, which when stacked together with pure translational repetition reproduces the whole crystal ? 晶胞參數(shù) Unit Cell Dimensions a, b and c are the unit cell edge lengths. a, b and g are the angles (a between b and c, b between c and a , g between a and b c .) 晶向和晶面指數(shù) 2. 晶體結(jié)構(gòu)與空間點(diǎn)陣 B ? 等同點(diǎn)與結(jié)點(diǎn) ? 結(jié)構(gòu)基元：原子、分子或其集團(tuán) ? 晶體結(jié)構(gòu)＝空間點(diǎn)陣＋結(jié)構(gòu)基元 The 14 possible BRAVAIS LATTICES {note that spheres in this picture represent lattice points, not atoms!} 2. 晶體結(jié)構(gòu)與空間點(diǎn)陣 C 7 crystal Classes Crystal system Unit cell shape Essential symmetry Space lattices Cubi a=b=c a=b=g=90 Four threefold axes P I F Tetragonal
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號(hào)-1