1. Molecular Geometry (VSEPR theory) Prem D. Sattsangi Christopher L. Byers (programmer) © 2010 Prem D. Sattsangi Christopher L. Byers (programmer) © 2010

2. Learning Molecular Geometry bondsunshared electron pairs (E.P.) The total number of bonds and unshared (non- bonded) electron pairs (E.P.) determine the electron domain around the central atom. solid lines Bonds will be shown as solid lines. balloons Non-Bonded E.P. will be shown as balloons. O H H E.G.

3. Trigonal Planar Structures A = Central Atom X = Bonded Atom (or Non-Bonded E.P.) 120° angles, sp 2 hybridization Molecular Geometry “Bent” X A X 120° X A X X Molecular Geometry “Trigonal Planar” A X X X 120° Top Views Side View In molecular geometry the orbitals are not shown.

4. Aluminum chloride AlCl 3

5. Nitrate Ion NO 3 -

6. Nitrite Ion NO 2 -

7. Tetrahedral Structures X X A X 109.5° A = Central Atom X = Bonded Atom (or Non-Bonded E.P.) 109.5° angles, sp 3 hybridization Molecular Geometry “Trigonal Pyramidal” Molecular Geometry “Bent” X X A X X 107° X A X 104.5° Each Non-Bonded E.P. reduces the angle by 2.5°.

8. Methane CH 4

9. Ammonia NH 3

10. Water H 2 O

11. Trigonal Bipyramidal Structures X X A X X X 120° 90° Axial Equatorial A = Central Atom X = Bonded Atom (or Non-Bonded E.P.) 90° angle between Axial and Equatorial bonds 120° angle between Equatorial bonds, sp 3 d hybridization X X A X X Molecular Geometry “Seesaw” Molecular Geometry “T-Shaped” X X A Molecular Geometry “Linear” X X A X The non-bonded E.P. occupies the equatorial position.

12. Phosphorus pentachloride PCl 5

13. Sulfur tetrafluoride SF 4

14. Chlorine trifluoride ClF 3

15. Octahedral Structures 90° A = Central Atom X = Bonded Atom (or Non-Bonded E.P.) 90° angles, sp 3 d 2 hybridization Molecular Geometry “Square Pyramidal” Molecular Geometry “Square Planar” X X X A X X X X X A X X 90° X X A X X X

16. Sulfur hexafluoride SF 6

17. Bromine pentafluoride BrF 5

18. Review Quiz 1 Name the molecular geometry of the following compounds. N O O NO 2 H N H H NH 3 Trigonal PlanarTetrahedral Trigonal Pyramidal Bent O H H H2OH2O F B F F BF 3 sp 2 hybrid H H C H H CH 4 sp 3 hybrid

19. Review Quiz 2 Name the molecular geometry of the following compounds. Cl P PCl 5 sp 3 d hybrid Trigonal BipyramidalSeesaw Linear F F S F F SF 4 T-Shaped F F Xe XeF 2 F F Cl F ClF 3

20. Review Quiz 3 Name the molecular geometry of the following compounds. F F F S F F F SF 6 sp 3 d 2 hybrid F F Br F F F BrF 5 F Xe F F F XeF 4 Octahedral Square Pyramidal Square Planar

21. Trigonal Bipyramidal (has 5 electron domains) # BondsNon-Bond E.P.Geom. 50Trig. Bipyr 41Seesaw 32T-Shaped 23Linear ClXe S