Chemistry 401

Intermediate Inorganic Chemistry

University of Rhode Island

Final Exam

December 19, 2008
open book, open notes

All references are to volume 47 of Inorganic Chemistry (2008).

1. Vaqueiro (pages 20 – 22) prepared (C7H10N)(In9Se14) crystals (C7H10N = 3,5-dimethylpyridinium ion). Find the oxidation states and electron configurations for the In and Se in the anion.

Answer

2. Tooyama, Braband, Spingler, Abram, and Alberto (pages 257 – 264) studied the chemistry of TcO4. Write the Lewis dot structure for TcO4 and indicate the formal charge on each atom. Predict the reaction product of TcO4 with BF3·OEt2.

Answer

3. Tregenna-Priggott (pages 448 – 453) investigated the Jahn-Teller distortion in Mn(III) complexes. His paper is aimed at explaining why tetragonal compression is a rare occurrence for Mn(III). Explain the factors that account for the idea that compression is rare for Mn(III).

Answer

4. Lau, et al, (pages 632 – 644) reacted cpCr(CO)3 (cp = η5-C5H5) with a variety of dithiadiazolyls. Name the complex and predict its stability.

Answer

5. Krahl, Ahrens, Scholz, Heidemann, and Kemnitz (pages 663 – 670) solved the structure of (NH4)3GaF6 using NMR methods. Write the Lewis structure for each ion, predict all of the bond angles in each ion, and give the point group for each ion. The compound crystallizes in a cubic structure: which ion determines the lattice and which ion fills the holes. Explain your reasoning.

Answer

6. Karaghiosoff, et al, (pages 1007 – 1019) examined the reactivity of the highly energetic methylated aminotetrazole salts. Balance the reaction: (C2H6N5)(NO3)(s) + O2(g) → CO2(g) + H2O(l) + N2(g). What is the energetic driving force for this reaction.

Answer

7. Zou, Xiang, Wei, Li, and Evans (pages 1361 – 1369) described a new synthetic route to ZnGa2O4, a wide band gap semiconductor. The band gap in this oxide is about 4.4 eV. What would you use to dope this material to reduce the band gap. Would this give a p-type or n-type semiconductor. Explain your reasoning.

Answer

8. Khater, Guillemin, Bajor, and Veszprémi (pages 1502 – 1511) investigated tellurols, RTeH. Write the Lewis dot structure for HTeCH3, predict the H-Te-C bond angle, and draw a qualitative MO diagram. The authors found two low energy peaks in the photoelectron spectrum of this compound at 8.46 and 11.00 eV. Assign the two observed peaks based on your MO diagram.

Answer

9. Welch, Holtrichter-Roessmann, and Stephan (pages 1904 – 1906) report the reaction of B(C6F5)3 with a number of phosphines. Estimate the enthalpy of reaction of trimethylphosphine with trimethylboron. Would you expect B(C6F5)3 to be a stronger or weaker Lewis acid with respect to trimethylphosphine. Explain your reasoning.

Answer

10. Mukherjee, Lloret, and Mukherjee (pages 4471 – 4480) study a new ligand, [2,4-ditert-butyl-6-{[(2-pyridyl)ethyl](2-hydroxybenzyl)-aminomethyl}-phenol. They synthesized complexes with Co2+, Ni2+, and Cu2+ and found the following data:

Ion

λmax (nm)

ε (M–1cm–1)

μeff (BM)

Co2+

750

30

4.4

Ni2+

680

70

2.9

Cu2+

770

400

1.3

Is the ligand a weak field or strong field? Explain your reasoning.

Answer