S 4

1. S4 C3 S6

3. pz, (dxz, dyz) s A’1 (px , py): E’ pz: A”2 (dx2 – y2, dxy): E’ (dxz, dyz): E’’ dz2: A’1

4. -1 0 1 3 0 -3

5. f) Now shift to the C3vpoint group and obtain the irreducible reps to which the pi bonding NH2 unit orbitals belong. G = A1 + E

6. A1 E1 E2

7. A1 E1 E2 On going from C3v to D3h maintain same behavior for the C3v operations (E, C3 and sv). Thus A1 in C3v could be either A’1 or A’’2. Choose A2’’ since it is antisym for sh. Likewise, E could be either E’ or E’’ Choose E’’ since it is antisym for sh. Thus A”2 and E’

8. i) Show bonding between the Si orbitals and the symmetry adapted NH2 orbitals A2” Si Orbitals s A’1 (px , py): E’ Pz: A”2 (x2 – y2, xy): E’ (xz, yz): E’’ z2: A’1 E” (1) E” (2)

12. E C2(y) sx,z i sx,z i = C2(y) C2(y)

13. E C2(y) C2’(-xy) sxy,z i C2’(-xy)

14. E C2(y) C2’(-xy) C4 (z) C2 (z) sx,z sxy,z C4 (z)

15. E C2(y) C2’(-xy) C4 (z) C2 (z) s-xy,z C2 (z) sxy,z s-xy,z

16. E C2(y) s-xy,z C2’(-xy) C4 (z) C2 (z) sh s-xy,z C2’(-xy) sh D4h

17. Coordination number 1 Very rare, bulky ligands, linear structures, no possible isomers

18. Coordination number 2 Also rare, typical of d10, linear structures, no possible isomers

19. Coordination number 3 Also typical of d10, trigonal planar structures (rarely T-shaped), no possible isomers

20. Coordination number 4 Very common Tetrahedral (2 enantiomers if all ligands different) Square planar (2 geometrical isomer for two types of ligands) typical of d8

21. Tetrahedral Square planar

22. Coordination number 5 Trigonal bipyramidal (tbp) Square-based pyramidal sbp) Very similar energies, they may easily interconvert in solution (fluxionality)

24. Coordination number 6 Trigonal prism less common Octahedral most common

25. Some possible isomers in octahedral complexes cis-MA2B4 trans-MA2B4 fac-MA3B3 mer-MA3B3

26. Some examples of trigonal prismatic structures

27. Coordination number 7 Pentagonal bipyramidal Capped trigonal prismatic Capped octahedral

28. Examples of coordination number 7