ADVANCED INORGANIC CHEMISTRY QUIZ 4 November 29, 2012 INSTRUCTIONS: PRINT YOUR NAME > NAME.

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1 ADVANCED INORGANIC CHEMISTRY QIZ 4 November 29, 2012 INSTRCTIONS: PRINT YOR NAME > NAME. WORK all 4 problems SE THE CORRECT NMBER OF SIGNIFICANT FIGRES YOR SPPPLEMENTAL MATERIALS CONTAIN: A PERIODIC TABLE Water MO diagram C 2 v and D 5 h POINT GROP CHARACTER TABLEs Quiz 4 R = lit-atm/mol-k 1 (30) R = J/mol-K 2 (30) 3 (20) c = X 10 8 m/s 4 (20) h = X J-s TOTAL(100)

2 1. Give a short answer or explanation for the following. (a) Explain why s-p mixing must be considered for early second row diatomics such as B 2 and C 2, but s-p mixing is ignored for late second row diatomics such as O 2 and F 2. (b) Give at least two reasons how the use of symmetry helps in molecular orbital construction. The molecular orbital diagram for water is included in the quiz. Refer to it for (c) (e) (c) sing the diagram explain why a proton asttached to oxygen instead of hysrogen (d) The 1 b 2 orbital is called a pure non-bonding orbital. Explain what this means. (e) How does the molecular orbital diagram differ from the valence bond (Lewis structure ) description of water..

3 2. Consider the species, NO +, NO (neutral), and NO -. (these species have s-p mixing) (a) Sketch the energy levels of the molecular orbitals (just draw one diagram and populat it with the electrons for neutrsl NO. ). (b) Calculate the bond order of each species. (c) Rank the species in order of increasing bond length < < (d) Rank the species in order of increasing bond strength. < < (e) Which if any of the species is paramagnetic? Sketch the shape of one of the π* anti- (f) Sketch the lowest energy orbital s shape. bonding orbitals.

4 3. This problem runs over two pages.you will construct the symmetry adapted orbitals for BrF 3. Point group C 2 v (a) Construct reducible representastions for the group orbitals by applying the symmetry operations. E C 2 (z) σ v (xz) σ v (yz) s Γ= E C 2 (z) σ v (xz) σ v (yz) P (σ bond) Γ= E C 2 (z) σ v (xz) σ v (yz) Γ= p(π-bond(1)) E C 2 (z) σ v (xz) σ v (yz) Γ= p(π-bond(2)) (continue on next page)

5 (b) Reduce your representation to a sum of irreducible representations, and identify thre central aton that interacts with the orbital. (I did the first two) s or p σ Γ = 2 A 1 = s, pz + B 1 central atom orbitals s, pz px p(π-bond(1)) E C 2 (z) σ v (xz) σ v (yz) from previous page Γ= Reduce and identify the central atom orbitals. #A1 = #A2 = #B1 = #B2 = p(π-bond(1)) Γ = + + central atom orbitals p(π-bond(1)) E C 2 (z) σ v (xz) σ v (yz) from previous page Γ= Reduce and identify the central atom orbitals. #A1 = #A2 = #B1 = #B2 = p(π-bond(1)) Γ = + + central atom orbitals

6 3. A ion of O 2 F 5 5- has pentagonal bipyramidal geometry. The point group of the ion is D 5 h z y O F F F x F F O (b) The group orbitals for the O atoms (using the s orbitals) are shown below with their symmetries. To the right of the figures indicate which orbital will interact with the group orbital to form a molecular orbital. Consider the s, p, and d orbitals on. Sketch the shape of the bonding molecular orbital formed by this interaction. Group Bonding Orbital orbital Molecular orbital (s) A 1 ' A 2 " Continues on next page.

7 (b) The group orbitals for the F atoms (using the s orbitals) are shown below with their symmetries. The ion has been rotated to show the view perpendicular to the xy plane. To the right of the figures indicate which orbital will interact with the group orbital to form a molecular orbital. Consider the s, p, and d orbitals on. Sketch the shape of the bonding molecular orbital formed by this interaction. Group Bonding Orbital orbital Molecular orbital(s) y A 1 ' E 1 ' E 1 "

9 Character table for D 5 h Character table for point group D 5h (x axis coincident with C' 2 axis) D 5h E 2C 5 2(C 5 ) 2 5C' 2 h 2S 5 2(S 5 ) 3 5 v linear functions, rotations quadratic functions A' x 2 +y 2, z 2 A' R z - E' cos(2 +2cos( cos(2 +2cos(4 0 (x, y) - E' cos(4 +2cos( cos(4 +2cos(2 0 - (x 2 -y 2, xy) A'' A'' z - E'' cos(2 +2cos( cos(2-2cos(4 0 (R x, R y ) (xz, yz) E'' cos(4 +2cos( cos(4-2cos(

10 3. This problem runs over two pages. You will construct the symmetry adapted group orbitals for BrF 5. Point group C 4 v (a) Construct reducible representations for the group orbitals by applying the symmetry operations. Hint: they are all odd numbers. E 2 C 4 (z) C 2 (z) 2 σ v (xz) 2σ d (bisectror of xz and yz) Γ = E 2 C 4 (z) C 2 (z) 2 σ v (xz) 2σ d (bisectror of xz/yz) When you finish bring it to me to grade so you can do the next part.

11 Reproduce your representation here and reduce it. Γ = E 2 C 4 (z) C 2 (z) 2 σ v (xz) 2σ d (bisectror of xz/yz) Reduce and identify the central atom orbitals. #A1 = #A2 = #B1 = #B2 = #E = (s-bond(1)) Γ = Not all blanks A1 A2 B1 B2 E may be needed central atom orbitals (se s, p, and d) A1 A2 B1 B2 E

12 4. The following involves drawing the pi molecular orbitals for a square planar complex such as XeF 4. The group orbital symmetry is as shown. Identify the central atom orbital that interacts, and draw the bonding combination for each set.

Quiz 5 R = lit-atm/mol-k 1 (25) R = J/mol-K 2 (25) 3 (25) c = X 10 8 m/s 4 (25)

Quiz 5 R = lit-atm/mol-k 1 (25) R = J/mol-K 2 (25) 3 (25) c = X 10 8 m/s 4 (25) ADVANCED INORGANIC CHEMISTRY QUIZ 5 and FINAL December 18, 2012 INSTRUCTIONS: PRINT YOUR NAME > NAME. QUIZ 5 : Work 4 of 1-5 (The lowest problem will be dropped) FINAL: #6 (10 points ) Work 6 of 7 to 14