1. Summer 2001 Notes June 13 June 15 June 18 June 20 July 2 Fall 2001 Lectures 9/28 10/1 10/3 10/5 – 10/8

2. 2+ [Co(H 2 O) 6 ] 2+

3. Hydrolysis by complex ions

4. + H 2 O (l) + H 3 O +

5. + H 2 O (l) + H 3 O + acid Conjugate base

6. Fe(H 2 O) 6 3+ (aq) + H 2 O(l) H 3 O + (aq) + Fe(H 2 O) 5 OH 2+ (aq)

7. Fe(H 2 O) 6 3+ (aq) + H 2 O(l) H 3 O + (aq) + Fe(H 2 O) 5 OH 2+ (aq) K a = [H 3 O + ][Fe(H 2 O) 5 OH 2+ ] [Fe(H 2 O) 6 3+ ] = 7.7 x 10 -3

8. Fe(H 2 O) 6 3+ (aq) + H 2 O(l) H 3 O + (aq) + Fe(H 2 O) 5 OH 2+ (aq) K a = [H 3 O + ][Fe(H 2 O) 5 OH 2+ ] [Fe(H 2 O) 6 3+ ] = 7.7 x 10 -3 pH of 0.10 M Fe(H 2 O) 6 3+

9. [Fe(H 2 O) 6 3+ ][H 3 O + ] [Fe(H 2 O) 5 OH 2+ ] Start change equil. 0.10  0 0

10. pH of 0.10 M Fe(H 2 O) 6 3+ [Fe(H 2 O) 6 3+ ][H 3 O + ] [Fe(H 2 O) 5 OH 2+ ] Start change equil. 0.10  0 0 -x +x +x

11. pH of 0.10 M Fe(H 2 O) 6 3+ [Fe(H 2 O) 6 3+ ][H 3 O + ] [Fe(H 2 O) 5 OH 2+ ] Start change equil. 0.10  0 0 -x +x +x 0.10 - x x x

12. pH of 0.10 M Fe(H 2 O) 6 3+ [Fe(H 2 O) 6 3+ ][H 3 O + ] [Fe(H 2 O) 5 OH 2+ ] Start change equil. 0.10  0 0 -x +x +x 0.10 - x x x Ka =Ka = (x)(x) (0.10 - x) = 7.7 x 10 -3

13. Ka =Ka = (x)(x) (0.10 - x) = 7.7 x 10 -3 pH of 0.10 M Fe(H 2 O) 6 3+

14. Ka =Ka = (x)(x) (0.10 - x) = 7.7 x 10 -3 pH of 0.10 M Fe(H 2 O) 6 3+ x 2 = (7.7 x 10 -3 )(0.10 - x)

15. Ka =Ka = (x)(x) (0.10 - x) = 7.7 x 10 -3 pH of 0.10 M Fe(H 2 O) 6 3+ x 2 = (7.7 x 10 -3 )(0.10 - x) x 2 + (7.7 x 10 -3 )x - 7.7 x 10 -4 = 0

16. Ka =Ka = (x)(x) (0.10 - x) = 7.7 x 10 -3 pH of 0.10 M Fe(H 2 O) 6 3+ x 2 = (7.7 x 10 -3 )(0.10 - x) x 2 + (7.7 x 10 -3 )x - 7.7 x 10 -4 = 0 x = 0.024

17. Ka =Ka = (x)(x) (0.10 - x) = 7.7 x 10 -3 pH of 0.10 M Fe(H 2 O) 6 3+ x 2 = (7.7 x 10 -3 )(0.10 - x) x 2 + (7.7 x 10 -3 )x - 7.7 x 10 -4 = 0 x = 0.024 pH = 1.6

18. Symmetry

19. Molecular symmetry BF 3

20. Symmetry Molecular symmetry BF 3 B FF F

21. Symmetry Molecular symmetry BF 3 B FF F B FF F

22. Symmetry Molecular symmetry BF 3 B FF F Rotate 120 o around an axis through B to the plane of the screen.

23. Symmetry Molecular symmetry BF 3 Rotate 120 o B FF F B FF F

24. Symmetry BF 3 Rotate 120 o B FF F B FF F Since the fluorines are all identical, we cannot tell the two molecules apart. =

25. Symmetry B FF F B FF F Since the fluorines are all identical, we cannot tell the two molecules apart. = Rotate 120 o

26. Symmetry B FF F Since the fluorines are all identical, we cannot tell the two molecules apart. = Rotate 120 o B FF F B FF F =

27. Symmetry BF 3 Rotate 120 o B FF F B FF F = This is a 3-fold axis of symmetry. A third 120 o rotation brings the molecule back to the starting position.

28. Symmetry BF 3 B FF F Rotate 180 o around the B - F axis.

29. Symmetry BF 3 Rotate 180 o around the B - F axis. B FF F B FF F

30. Symmetry BF 3 Rotate 180 o around the B - F axis. B FF F B FF F = A second 180 o rotation gives the original molecule.

31. Symmetry BF 3 Rotate 180 o around the B - F axis. B FF F B FF F This is a 2-fold symmetry axis =

32. Symmetry BF 3 B FF F BF 3 has 3 2-fold symmetry axes.

33. Symmetry BF 3 B FF F B F mirror

34. Symmetry BF 3 B FF F B F Mirror plane of symmetry B FF F =

35. Symmetry BF 3 B FF F B F BF 3 has 3 mirror planes of symmetry along the B-F bonds. B FF F =

37. There is a mirror plane in the plane of the molecule.

38. B FF F 1 3-fold axis normal to plane 3 2-fold axes along B - F bonds 3 mirror planes along bonds 1 mirror plane in molecular plane

39. 2+

40. 4-fold rotation axis

41. 2+ 4-fold rotation axis = 4 90 o operations to get back to original configuration.

42. 2+ 4-fold rotation axis = 4 90 o operations to get back to original configuration. The octahedral complex will have 3 4-fold axes.

43. 2+ Mirror planes?

44. 2+ Mirror planes? Co O O O O

45. 2+ Mirror planes? Co O O O O 3 mirror planes with Co and 4 H 2 O’s.

46. 2+ Mirror planes? Co O O O O

47. 2+ Mirror planes? Co O O O O

48. 2+ Any other rotation axes?

49. 2+ Any other rotation axes?

50. 2+ Any other rotation axes? Octahedral complexes have 3-fold axes.

51. 2+ Any other symmetry elements?

52. 2+ Any other symmetry elements? Inversion center

53. 2+ Any other symmetry elements? Inversion center The Co is the inversion center.

54. 2+ Any other symmetry elements? Inversion center The Co is the inversion center. At any point where there is a ligand, there is a ligand the same distance in the opposite direction.

55. Tetrahedron

56. Perchlorate ClO 4 -

57. Tetrahedron Perchlorate ClO 4 - 1 2 3 4 1 2 3 4 = 2-fold

58. Tetrahedron Perchlorate ClO 4 - 1 2 3 4 1 2 3 4 = Mirror plane

59. Tetrahedron Perchlorate ClO 4 - 1 2 3 4 1 2 3 4 = 3-fold axis Cl-O3

60. Tetrahedron Perchlorate ClO 4 - 1 2 3 4 4 3-fold rotations 3 2-fold rotations 3 mirror planes + others

61. octahemioctahedron

62. 4-fold rotation axes

63. octahemioctahedron 4-fold rotation axes This is not a 3-fold

64. octahemioctahedron 4-fold rotation axes This is not a 3-fold

65. octahemioctahedron 4-fold rotation axes This is not a 3-fold

66. octahemioctahedron 4-fold rotation axes This is not a 3-fold a b The points a and b are related.

67. octahemioctahedron 4-fold rotation axes a b The combination of 120 o rotation and a mirror leads to a new symmetry element

68. octahemioctahedron 4-fold rotation axes a b The combination of 120 o rotation and a mirror leads to a new symmetry Element - S 3

69. Symmetry elements to look for- rotations mirrors inversions

71. Crystals and solid-state structure

72. octahedron

73. Crystals and solid-state structure

74. Tetrahedral coordination

75. Crystals and solid-state structure Tetrahedral coordination C - C = 1.544 Å

76. Å = ångström = 10 -10 m

77. The ångström is a useful unit when describing bonding distances.

78. Symmetry of a tetrahedron

79. Tetrahedrons and cubes have 3-fold axes of symmetry

80. Graphite Crystal

81. Graphite Structure

82. Hexagonal bond array leads to hexagonal crystal

83. Graphite Structure Bonds - strong attraction

84. Graphite Structure Bonds - strong attraction van der Waal’s forces- weak attraction

85. Hard structure - bonds are 3-dimensional Soft structure - bonds are in two dimensions

86. Hard structure - bonds are 3-dimensional Soft structure - bonds are in two dimensions van der Waal’s forces easy to break

87. BuckyBall a fullerene C 60 Individual molecule of carbon atoms OFB page 79 crystals.

88. BuckyBall a fullerene C 60

90. NaCl

95. SiO 2