2.unit cell content: Every crystalline solid can be described in terms of one of the seven types of unit cells. types of unit cells edge-length angle examples cubic 立方晶系 a=b=c a=B=y=90 NaCl a=b=c rhombohedral 三方晶系 a=B=y≠90 AbO; 菱面体晶胞 tetragonal 四方晶系 a=b≠c a=B=y=90 SnO hexagonal 六方晶系 a=b≠c a=B=90°，y=120 AgI orthorhombic 正交晶系 a≠b≠c a=B=y=90 HgCk monoclinic 单斜晶系 a≠b≠c a=B=90°，y≠90° KCIO3 triclinic 三斜晶系 a≠b≠c a≠B≠y≠90 CuSO5H2O 14 Bragg lattices which belong to 7 crystal systems.Each system has a primitive cell,and some allow face or body centering,as well as the rhombohedral centering in the trigonal system
2. unit cell content： 14 Bragg lattices which belong to 7 crystal systems. Each system has a primitive cell, and some allow face or body centering, as well as the rhombohedral centering in the trigonal system. Every crystalline solid can be described in terms of one of the seven types of unit cells. cubic rhombohedral tetragonal hexagonal orthorhombic monoclinic triclinic edge-length angle examples 立方晶系 a = b = c α=β=γ= 900 NaCl 三方晶系 a = b = c α=β=γ≠900 Al2O3 四方晶系 a = b≠c α=β=γ= 900 SnO2 六方晶系 a = b≠c α=β= 900 , γ= 1200 AgI 正交晶系 a≠b≠c α=β=γ= 900 HgCl2 单斜晶系 a≠b≠c α=β= 900 , γ≠ 900 KClO3 三斜晶系 a≠b≠c α≠β≠γ≠ 900 CuSO4·5H2O types of unit cells 菱面体晶胞
Monoclinic Triclinic 14 Bragg lattices Orthorhombic P Tetragonal Trigonal/Hexagonal P Trigonal R Cubic
14 Bragg lattices
10.1.2 Crystal defects(晶体缺陷) l.Schottky defect(Latent defects,本征缺陷) A Schottky defect consists of an atom or ion vacancy in a crystal lattice,but the stoichiometry of a compound (and thus electrical neutrality)must be retained.In a metal lattice,a vacant atom site may be present.由于晶体中晶格结点上的微粒热涨落所导致的 缺陷
10.1.2 Crystal defects (晶体缺陷 ) 1.Schottky defect (Latent defects,本征缺陷 ) A Schottky defect consists of an atom or ion vacancy in a crystal lattice, but the stoichiometry of a compound (and thus electrical neutrality) must be retained. In a metal lattice, a vacant atom site may be present.由于晶体中晶格结点上的微粒热涨落所导致的 缺陷
2.Frenkel defect In a Frenkel defect,an atom or ion occupies a normally vacant site,leaving its own'lattice site vacant. 6)
2. Frenkel defect In a Frenkel defect, an atom or ion occupies a normally vacant site, leaving its ‘own’ lattice site vacant
2.Impurity defects(杂质缺陷) Defects caused by incorporation of impurity into the crystal Si 活动电子 Movable electrons 正电空穴 Positively charged vacancy Electron-excess Electron-deficient
2. Impurity defects (杂质缺陷 ) Electron-excess Electron-deficient Positively charged vacancy Movable electrons Defects caused by incorporation of impurity into the crystal