1. Chapter 6 Solid-State Chemistry

2. Problems n n 6.9, 6.13, 6.14

3. Unit Cells?

6. Unit Cells 7 types n n cubic n n orthorhombic n n tetragonal n n hexagonal n n monoclinic n n triclinic n n trigonal/rhombohedral

7. Bravais Lattices n n 14 n n Figure 6.1, pg. 253

8. Space Groups n n 235 discrete structural arrangements n n some selected crystal systems n Table 6.1, pg. 254

9. Top 6 Space Groups n n as reported in literature n P2 1 /c29.2%monoclinic n P2 1 2 1 2 1 18.8orthorhombic n P -111.1triclinic n P2 1 10.9monoclinic n C2/c 5.4monoclinic n Pnma 1.5orthorhombic n P2 1 2 1 2 1.0orthorhombic

10. Structure Determination

11. Diffraction Conditions

12. n Solid-State Resources CD n Chapter 4 Diffraction n Quicktime Movie

13. Diffraction Conditions

14. Why monochromatic radiation?

15. Why use the shorter wavelength?

17. Reciprocal Lattice

18. Optical Transforms n Solid-State Resources CD n Chapter 4 Diffraction n Quicktime Movies

19. Discovery Slide

21. VSEPR Slide

22. Powder Diffraction Line spectrum for BaTi Zr O.75.253

23. Powder Diffraction n n ASTM cards n n dissertation

24. Single Crystal n n diffractometer n goniometer

25. X-ray Diffractometer

26. X-ray Diffractometer with CCD Detector

27. Goniometer Head for Single Crystal

28. Miller Indices n describe which plane of atom is interacting with the x-rays n used to calculate the reciprocal lattice parameters

29. Miller Indices

31. Reciprocal Lattice Cubic (1/d hkl ) = (h 2 + k 2 + l 2 ) 1/2 /a

32. Reflection Intensity |F o | " p I n n positive or negative root n n “phase problem” n n solve using Patterson methods when heavy atom is present n n solve using direct methods

33. Estimate of Error R = | F o - F c | / F o

34. Systematic Absences n n laser & ICE slides

35. Grains and Close Packing in Metals Grains in a polycrystalline material

36. Defects in Solids n Solid-State Resources CD n Chapter 6 Diffraction n Quicktime Movies

37. Dislocations

38. Work Hardening

39. Band Theory

40. Bands

41. Bands in Metals

42. Optical Properties of Metals Some possible electronic transitions in a half-filled band of a metal

43. Metallic Sea of Electrons High thermal conductivity High electrical conductivity High reflectivity of visible light Electrons are not bonded to any particular atom and are free to move about in the solid.

44. Electrical Conductivity Conductivity (  -cm ) –1

45. Electrical Conductivity Conductivity of metals decreases with temperature as atomic vibrations scatter free electrons. Conductivity of semiconductors increases with temperature as the number of carriers increases.

46. Bands and Electrical Conductivity n Solid-State Resources CD n Chapter 7 Bonding n Quicktime Movies n start with Movie Sand Bands n end with Movie Photocell

47. Optical Properties of Semiconductors

48. Band Gap Energy and Color

49. Semiconductors

50. Semiconductors two requirements n average number of valence shell electrons equals four n diamond (pure Si or Ge) crystal structure n or zinc blende (1:1 stoichiometry) crystal structure

51. Band Gap and Periodic Properties ElementUnit Cell, ÅD o, kJ/molE g, eV (, nm) C3.573465.5(230) Si5.432221.1(1100) Ge5.661880.66(1900)  -Sn6.49146< 0.1(12,000) MaterialUnit Cell, Ų  E g, eV (, nm) Ge5.660.00.66(1900) GaAs5.650.41.42(890) ZnSe5.670.82.70(460) CuBr5.690.92.91(430)

52. Solid Solutions 0.0 AZ 1.00.2 AZ 0.80.4 AZ 0.6 AZ 0.40.8 AZ 0.21.0 AZ 0.0

53. Semiconductors n Solid-State Resources CD n Chapter 7 Bonding n Quicktime Movies n start with Picture Periodic n end with Movie LED under Microscope

54. Buckminsterfullerenes C 60 & C 70 n n allotrope of carbon n n fcc n n lubricants, organic magnets, frequency doubling materials, and substrates for growing diamonds

55. Buckminsterfullerenes M 3 C 60 n n high temperature superconductor

56. Buckminsterfullerenes

57. Superconductivity n n Hg was discovered to be superconducting ar 4 K in 1911 n n many other metals are superconducting < 10 K (Al family, Sn, Pb, Ti, V, Zn, Cd, several 2nd & 3rd transition series) n n some alloys

58. Superconductivity n n 1-2-3 Superconductors (MBa 2 Cu 3 O 7-8 ) n n liquid nitrogen temperature superconductors

59. Superconductivity n n Loss of Resistance n Cooper pairs n n Meissner Effect

60. Superconductivity n n Perovskite n CaTiO 3

61. Superconductivity n Solid-State Resources CD n Chapter 9 Thermodynamics n Quicktime Movies n start with Movie Superconductivity Setup n end with Movie Superconductivity Small Magnet