Chemistry 401

Intermediate Inorganic Chemistry

University of Rhode Island

Final Exam

December 21, 2000
open notes, open book

All references are to articles from Inorganic Chemistry, 2000, 39.

1. D. L. Fiacco, A. Toro, and K. R. Leopold (p. 37-43) investigated the gas phase structure of the Lewis acid/base complex (CH3)3N–SO3. Draw the Lewis dot structure for this compound, estimate the C-N-S and N-S-O bond angles (± 2o), and indicate the hybridization at the N and S atoms.

Answer

2. M. M. Hosain and K. Matsumoto (p. 247-250) used the pentasulfide anion, S52–, as a tridentate ligand in the complex Ru(P(OCH3)3)3S5. Draw the Lewis dot structure of the pentasulfide anion (assume the octet rule is obeyed and there is a linear connectivity between sulfur atoms) and indicate the formal charge and formal oxidation number on each S atom. Name the metal complex. P(OCH3)3 is a neutral ligand named trimethylphosphite.

Answer

3. R. Churland, U. Frey, F. Metz, and A. E. Merbach (p. 302-307) prepared the complexes [M(CO)2Cl2] (M = Rh, Ir). Are these complexes expected to be stable by the effective atomic number rule? Why or why not? If not, what reactivity would you anticipate?

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4. B. Schüpp, P. Heines, A. Savin, and H.-L. Keller (p. 732-735) studied the pressure induced redox reaction: Cs2PdI4–I2 → Cs2PdI6. Which atom is oxidized and which atom is reduced? The high-pressure phase (Cs2PdI6) is a close-packed structure (face-centered cubic); which ion establishes the lattice packing and which atom fills holes? Why?

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5. J. L. Manson, E. Ressouche, and J. S. Miller (p. 1135-1141) found that the room temperature magnetic moment of Cr(C(CN)3)2 was 4.7 bohr-magnetons. Is this complex high spin or low spin? To deduce the charge on tricyanomethide, draw the Lewis dot structure assuming that all atoms maintain octets. Tricyanomethide is found to have a D3h symmetry. Is this consistent with your Lewis dot structure? Why or why not? If it is not consistent with your Lewis dot structure, draw a Lewis dot structure that is consistent with D3h symmetry.

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6. B. Saha and D. M. Stanbury (p. 1294-1300) studied the reaction [Ru(bpy)3]2+ + Cl2 → [Ru(bpy)3]3+ + Cl. Balance the reaction and estimate Eo for this reaction under standard acidic conditions. Would you expect the reaction mechanism to be inner sphere or outer sphere? Why? bpy = 2,2'-bipyridine.

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7. O. Gourdon, J. Hanko, F. Boucher, V. Petricek, M.-H. Whangbo, M. G. Kanatzidis, and M. Evain (p. 1398-1409) calculated the electronic band structure for K1/3Ba2/3AgTe2. Would you expect this material to be a p-type or n-type semiconductor? Hint: assume that the metal ions exist in their most common oxidation states.

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8. R. P. Singh and J. M. Shreeve (p. 1787-1789) synthesized (C6F13)2P(O)OH. Would you expect this acid to have a pKa higher or lower than phosphoric acid? Briefly explain your reasoning.

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9. R. Küster, T. Drews, and K. Seppelt (p. 2784-2786) prepared PF3H+. Draw the Lewis dot structure, predict all of the bond angles to ± 2o, indicate the hybridization on the P atom, and give the point group for this cation.

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10. A. D. Richardson, K. Hedberg, and G. M. Lucier (p. 2787-2793) measured the structures of gas-phase WF6, ReF6, OsF6, IrF6, and PtF6. The average M-F bond distances were found to be 1.829 Å, 1.829 Å, 1.828 Å, 1.839 Å, and 1.852 Å, respectively. Are these values consistent with what you would expect based on periodic trends? Why or why not? Find the LFSE for each of these complexes. How would you expect the LFSE to affect the bond lengths? Which of these complexes would you expect to be Jahn-Teller active? For those that are Jahn-Teller active, predict the mode of distortion.

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