无机化学无机化学英文PPT (5).ppt

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1、9.1 Crystal structure and type1.The features of crystal structure and lattice theoryCharacteristics:1.a geometric shape 2.a fixed melting point 3.Anisotropy石英石英quartz硫硫sulphur黄铁矿黄铁矿pyrite金刚石和石墨金刚石和石墨Diamond and graphite Crystal microstructure is analysis via X-ray by Dr.Laue started in 1912,The resu

2、lts show that the cyclical repeat regularity inside the crystal species:the crystal is composed of space lattice(or called grid).In which,a lattice represents a certain number of atoms(or ions and molecules)unit via recovered translation.Different types of crystals composed of different combination

3、units In the microscopic space of crystals,atoms exhibit the property of periodic and orderly arrangement -translational symmetry,which is a common feature of crystals.Microscopic characteristics of crystals-translational symmetry晶体的内部结构晶体的内部结构:1.晶格晶格 2.晶胞晶胞晶胞：晶胞：晶体的最小重复单元，通过晶胞在晶体的最小重复单元，通过晶胞在空间平移无限

4、地堆砌而成晶体空间平移无限地堆砌而成晶体 晶胞的两个要素：晶胞的两个要素：1.晶胞的大小晶胞的大小与与形状：形状：2.晶胞的内容：晶胞的内容：粒子的种类，数目及它在晶胞中的相对位置。粒子的种类，数目及它在晶胞中的相对位置。The internal structure of the crystal:1.lattice 2.unit cellCell:is defined as the smallest repeating unit of a crystal via infinitely shifting and aggregating in the spatial configuationsTw

5、o elements of a cell:1.Size and shape 2.Contents of the cell:The type,number,and relative position of the species in the cell.Seven crystal systemscrystal system crystal axis axis included Angle real examplecubic a=b=c =90 NaCl,CaF2,ZnS,Cuquartet a=b c =90 SnO2,MgF2,NiSO4,Snorthogonal a b c =90 K2SO

6、4,BaCO4,HgCl2,I2three parties*a=b=c =90 Al2O3,CaCO3,As,Bi a=b c =90,=120 monoclinic a b c =90,90 KClO3,K3Fe(CN)6,Na2B4O7triclinic a b c 90 CuSO45H2O,K2Cr2O7six parties a=b c =90,120 SiO2(quartz),AgI,CuS,MgThere are two types of cell parameters of the trigonal system:One type is rhombohedral lattice，

7、a=b=c，=90 The other one is the hexagonal P cell。1.Hexagonal close Packing:Space occupancy：74.05%The third layer is aligned with the first to produce ABAB.2.Dense accumulation of ballsHexagonal close Packing:hcpCoordination number:12Space occupancy:74.05%Metallic crystal:Dense accumulation of equal d

8、iameter spheresThe third layer is aligned with the first to produce ABAB.Hexagonal close packingBe,Mg,Sc,Ti,Co,Zn,Ti,Ru,Os,Te,Re,Zr,Hf2.Face centered cubic close packing：Space occupancy:74.05%Face centered cubic close packing:fccSpace occupancy:12Space ccupancy:74.05%The third floor is dislocated wi

9、th the first floor to arrange ABCABC.Face centered cubic dense packingFace centered cubic close packing:fccSuch as：Ca,Sr,Rh,Ir,Ni,Cu,Ag,Au,Al,Pd,Pt,Mn,Pb Noted:All atoms in the three layers ABC have the same geometric meaning;The coordination number is 12,and the space occupancy is 74.05%.3.Body centered cubic packing：Space occupancy:68.02%1.Ionic crystals is defined as a crystal is formed via ionic bonds by alternating positive and negative ions in a lattice3.Crystal typesFeatures:high melting point,high hardness,easy to dissolve in water,better conductor in aqueous solution or melt state