1. Solid State Chemistry (SSC)By-Saurav K. Rawat(Rawat DA Greatt)1

2. 2 3. CLASSIFICATION OF SOLIDSSOLID MATERIALSCRYSTALLINE POLYCRYSTALLINEAMORPHOUS(Non-crystalline)Crystal Structure 3Single Crystal 4. Single crystals have a periodic atomic structure across its4SINGLE CRYSTALSSingle CrystalsSingle PyriteCrystalAmorphousSolidwhole volume. At long range length scales, each atom is related to everyother equivalent atom in the structure by translational orrotational symmetry 5. Polycrystalline materials are made up of an aggregate of many small single Polycrystalline materials have a high degree of order over many atomic or5POLYCRYSTALLINE SOLIDScrystals (also called crystallites or grains).PolycrystallinePyrite form(Grain)molecular dimensions. Grains (domains) are separated by grain boundaries. The atomic order can varyfrom one domain to the next. The grains are usually 100 nm - 100 microns in diameter. Polycrystals with grains less than 10 nm in diameter are nanocrystalline 6. AMORPHOUS SOLIDSAmorphous (Non-crystalline) Solids are made up of randomlyorientated atoms , ions, or molecules that do not form definedpatterns or lattice structures.Amorphous materials have order only within a few atomic or moleculardimensions.Amorphous materials do not have any long-range order, but they havevarying degrees of short-range order.Examples to amorphous materials include amorphous silicon, plastics,and glasses.Amorphous silicon can be used in solar cells and thin film transistors.6 7. Centre of symmetryPlanes of symmetry Axes of symmetry 8. Definitions1. The unit cellThe smallest repeat unit of a crystal structure, in 3D,which shows the full symmetry of the structureThe unit cell is a box with: 3 sides - a, b, c 3 angles - , , 9. 3D 14 BRAVAIS LATTICES AND SEVEN CRYSTAL TYPES1) Cubic Crystal System (SC or P, BCC,FCC)2) Hexagonal Crystal System (SC or P)3) Triclinic Crystal System (SC or P)4) Monoclinic Crystal System (SC or P, Base-C)5) Orthorhombic Crystal System (SC or P, Base-C, BC, FC)6) Tetragonal Crystal System (SC or P, BC)7) Trigonal (Rhombohedral) Crystal System (SC or P)9TYPICAL CRYSTAL STRUCTURES 10. Crystal Structure 10 11. Three common Unit Cells in 3D11 12. Type ofCubicUnit CellUnit cellContent(z)AtomicRadiusPackingFractionPIFCC124a/2a2 /4a3/452.36%67.98%74.00% 13. Coordination Number in CubicLatticesSimple Cubic Lattice or Primitive (P)Face-centered Cubic Lattice (fcc)Body-Centered Cubic Lattice (bcc or I)Density of a substance,d = mass in unit cell/ volume of unit cell=n X atomic wt./ Avogadro no. X volume of unit cellWhere n= no. of particals in unit cell 14. Lattice planes (or crystal planes)and Miller indicesMiller gave the method to specify planes, Used intigershkl and enclosed them in parenthesis like (h,k,l). Todetermine Miller indices the intercepts by the givenplane on x,y and z axes (pa,qb,rc) are determined.P-1 : q-1 : r-1 = h : k : lThe lattice plane then will be (h,k,l) and the spacing isgiven by-d= a/(h2 + k2 + l2 ) 15. CRYSTALLOGRAPHY15Crystallography is a branch of science that deals with the geometricdescription of crystals and their internal atomic arrangement.Its important the symmetry of a crystal because it has a profound influenceon its properties.Structures should be classified into different types according to thesymmetries they possess.Energy bands can be calculated when the structure has been determined. 16. Miller Indices: Equivalent DirectionszyEquivalent directions due to crystal symmetry:x1231: [100]2: [010]3: [001]Notation used to denote all directions equivalent to [100] 17. The intercepts of a crystal plane with the axis defined by a set ofunit vectors are at 2a, -3b and 4c. Find the corresponding Millerindices of this and all other crystal planes parallel to this plane.The Miller indices are obtained in the following three steps:1. Identify the intersections with the axis, namely 2, -3 and4.2. Calculate the inverse of each of those intercepts,resulting in 1/2, -1/3 and 1/4.3. Find the smallest integers proportional to the inverse ofthe intercepts. Multiplying each fraction with theproduct of each of the intercepts (24 = 2 x 3 x 4) doesresult in integers, but not always the smallest integers.4. These are obtained in this case by multiplying eachfraction by 12.6 4 35. Resulting Miller indices is6. Negative index indicated by a bar on top. 18. zyMiller Indices of Planesz=xy=x=ax y z[1] Determine intercept of plane with each axis a [2] Invert the intercept values 1/a 1/ 1/[3] Convert to the smallest integers 1 0 0[4] Enclose the number in round brackets (1 0 0) 19. zyMiller Indices of Planesxx y z[1] Determine intercept of plane with each axis 2a 2a 2a[2] Invert the intercept values 1/2a 1/2a 1/2a[3] Convert to the smallest integers 1 1 1[4] Enclose the number in round brackets (1 1 1) 20. zyPlanes with Negative Indicesxx y z[1] Determine intercept of plane with each axis a -a a[2] Invert the intercept values 1/a -1/a 1/a[3] Convert to the smallest integers 1 -1 1[4] Enclose the number in round brackets 111 21. Closed Packing in crystalsSquare packed structure Hexagonal packedstructure 22. A sitesB sitesA sitesHCPFCCLayer Stacking Sequence= ABAB= ABCABC.. 23. Structures of Ionic SubstancesHaving Closed Packed LatticesIn ionic compounds one type of the ions ( cations oranions) form the closed packing structures whereas,the second type of ions occupy the voids as mentionedcompoiunn dthe Ifoonlsl ofowrminingg tcalobseled -packed structure Ions in voidsNaCl Cl- ions form CCP structure Na+ ions occupy alloctahedral voidsZnS S2- ions form CCP structure Zn2+ ions occupy alternatetetrahedral voidsFe3O4 or FeO,Fe2O3O2- ions form closed packed structure Fe2+ ions are in octahedralvoids. Fe3+ ions are in equalno. of Oh and Td voids 24. Factors affecting Coordination Number(i) Cation/anion radius ratio-Range of r+/r- C.N. of the Cationin the crystallatticeArrangement ofAnions aroundCations in thecrystal Lattice orGeometryExamples0.155-0.225 3 Planer Trigonal B2O3, BN0.225-0.414 4 Tetrahedral ZnS,ZnO0.414-0.732 6 Octahedral NaCl,AgX(X=F,Cl,Br)0.732-1.000 8 Cubic CsCl, CsBr(ii) Arrangement of Anions around the Cation(iii) Nature of void occupied by the Cation in closed packedstructure made by Anion 25. Sodium Chloride Structure (Rock Salt)Sodium chloride also crystallizes in acubic lattice, but with a different unitcell.Sodium chloride structure consists ofequal numbers of sodium andchlorine ions placed at alternatepoints of a simple cubic lattice.Each ion has six of the other kind ofions as its nearest neighbours.26 26. Structure of CsCl (Caesium Chloride) 27. Zinc BlendeExhibited by many semiconductorsincluding ZnS, GaAs, ZnTe and CdTe.GaN and SiC can also crystallize in thisstructure. 28. Zinc BlendeEach Zn bonded to 4 Sulfur- tetrahedralEquivalent if Zn and S are reversedBonding often highly covalentWurtziteZinc sulfide crystallizes in two differentforms: Wurtzite and Zinc Blende. 29. Wurtzite (Hexagonal) StructureThis is the hexagonal analog of the zinc-blendelattice. Can be considered as two interpenetratingclose-packed lattices with half of thetetrahedral sites occupied by another kind ofatoms. Four equidistant nearest neighbors, similar to azinc-blende structure.Certain compound semiconductors (ZnS, CdS,SiC) can crystallize in both zinc-blende (cubic)and wurtzite (hexagonal) structure. 30. CLASSIFICATION OF DEFECTS BASED ON DIMENSIONALITY0D(Point defects)1D(Line defects)2D(Surface / Interface)3D(Volume defects)VacancyImpurityFrenkeldefectSchottkydefectDislocation SurfaceInterphaseboundaryGrainboundaryTwinboundaryTwinsPrecipitateFaultedregionVoids /CracksStackingfaultsDisclinationDispirationThermalvibrationAnti-phaseboundariesInterstitialdefect 31. Point Defects Line Defects: DislocationsSchottky DefectsFrenkel DefectsMetal Excess Defects:The Color Centers( F-center; Ger: farbenzentre)Metal Deficiency DefectsEdge DislocationsScrew DislocationsVacancy DefectsInterstitial Defects 32. Point DefectsSchottkyDefectFrenkelDefectVacancydistortion Defectof planesSelf-interstitialdistortionof planesInterstitial AtomsInterstitial Defects 33. Metal Excess Defects: The Color CentersMetal Deficiency Defects 34. Line Defects: DislocationsEdge Dislocations Screw DislocationsFirst elementary dislocation type:edge dislocations 35. Rawats Creation-rwtdgreat@gmail.comrwtdgreat@yahoo.co.ukRawatDAgreatt/LinkedInwww.slideshare.net/RawatDAgreattGoogle+/blogger/Facebook/Twitter-@RawatDAgreatt+919808050301+919958249693