Crystal-structure-of-solids-Mechanical-Engineering-Department-机械工程系固体的晶体结构课件

Crystalstructureofsolids9/14/2023Crystalstructureofsolids8/41AgendaReviewSpacelatticeLatticeparametersUnitcell7crystalstructures14Bravaislattices9/14/2023AgendaReview8/4/20232ReviewQuickreviewofpreviousclassAtomicstructureAtomicbondsStructureofsolidsSOLIDStrongbondingLongrangeorder9/14/2023ReviewQuickreviewofprevious3Spacelattice3DregulararrangementofpointsinspaceHowcantheatomicarrangementinsolidsbemathematicallydescribed?Intwodimensions……XYXYgababg(a)inaCartesiansystem(b)inageneralsystem9/14/2023Spacelattice3Dregulararrang43DSpaceLatticeXYZabcbga9/14/20233DSpaceLatticeXYZabcbga8/4/25LatticeparametersTodefineanylattice6latticeparametersareneededa,b,c,(sides)a,b,g,(angles)Howmanyuniquespacelatticescanbederived?Only7suchlatticescanbederivedWhenatomsareplacedonthelatticepointswegetCRYSTALSTRUCTURES9/14/2023LatticeparametersTodefinean6UnitcellBasicbuildingblockinthegenerationofaspacelatticeabcgba9/14/2023UnitcellBasicbuildingblock7This(cornerofthecube)pointissharedbyeightunitcells.Thereforeonlyone-eighthofthepointbelongstoeachunitcell.9/14/2023This(cornerofthecube)poin87crystalstructures9/14/20237crystalstructures8/4/2023914BravaislatticesTriclinic PMonoclinic P CRhombohedral POrthorhombic P I F CTetragonal P IHexagonal PCubic P I FP=primitive I=innenzentric(bodycentered) F=facecentered C=basecentered9/14/202314BravaislatticesTriclinic 10Anexample9/14/2023Anexample8/4/202311SummarySpacelatticeLatticeparametersCrystalstructuresBravaislattices9/14/2023SummarySpacelattice8/4/202312PreviewCubicsystemSimplecubic(SC)Bodycenteredcubic(BCC)Facecenteredcubic(FCC)MillerindicesHexagonalsystem9/14