7.1.4 Types of Crystals crystal type 晶格节 粒子间 Physical properties 点粒子 作用力 rigidity 熔融导 e.g. m.p,b.p 硬度 电性 ionic ion 离子键 high big good NaCl atomic atom 共价键 high big fare SiOz atom high Cr, metallic 金属键 big ion low small good K,Hg 分子间 molecular molecule low small 力 fare dry ice mixed mixed mixed graphite
Physical properties 晶格节 点粒子 粒子间 作用力 m.p, b.p rigidity 硬度 熔融导 电性 e.g. ionic ion 离子键 high big good NaCl atomic atom 共价键 high big fare metallic atom ion 金属键 high low big small good Cr, K, Hg molecular molecule 分子间 力 low small fare dry ice SiO2 crystal type mixed mixed mixed graphite 7.1.4 Types of Crystals
§7.2 Metallic Crystals -7.2.1 The Structures of Metallic Crystals 7.2.2 Metallic Bond Theory 返 回
7.2.1 The Structures of Metallic Crystals §7.2 Metallic Crystals 7.2.2 Metallic Bond Theory
7.2.1 The Structures of Metal Crystals Metal crystals are composed of atoms or/and ions via metal bonds..金属键没有方向性，金属晶体内原子以配 位数高为特征。 Arrangements of particles in metal crystals Packing Spheres of homo-radii The main three types(常见的有三种)： 。Hexagonal Close Packing(六方密堆积)； ●Face-Centered Cubic Close Packing(面心立方密堆积) ●Body-Centered Cubic Packing(体心立方堆积)
Metal crystals are composed of atoms or/and ions via metal bonds. 金属键没有方向性，金属晶体内原子以配 位数高为特征。 7.2.1 The Structures of Metal Crystals The main three types(常见的有三种)： Hexagonal Close Packing(六方密堆积)； Face-Centered Cubic Close Packing(面心立方密堆积) Body-Centered Cubic Packing(体心立方堆积) Packing Spheres of homo-radii Arrangements of particles in metal crystals
1.Hexagonal close-packing:(hep) Each third-layer sphere is directly over a first-layer sphere.The layers repeat in their pattern in the manner ABAB... Coordination number((配位数)：I2 Spatial occupancy factor(空间占有率)：74.05%（自己计算）
1.Hexagonal close-packing: (hcp) Each third-layer sphere is directly over a first-layer sphere. The layers repeat in their pattern in the manner ABAB… Coordination number(配位数)：12 Spatial occupancy factor (空间占有率): 74.05%(自己计算) 1 2 3 5 4 6 1 2 3 5 4 6
A Coordination number(配位数)：12 B A Spatial occupancy factor (空间占有率)： B 74.05%(自己计算) A
Coordination number(配位数 ) ：12 74.05%(自己计算 ) Spatial occupancy factor (空间占有率): 1 2 3 5 4 6 A B 1 2 3 5 4 6 ABABA