Ch.23 - Transition Metals and Coordination Chemistry
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- Complete the exercises below. Which of the following objects is chiral: a. a left shoe, b. a slice of bread, c. a wood screw, d. a molecular model of Zn(en)Cl₂, e. a typical golf club?
Problem 79
- Complete the exercises below. Solutions of [Co(NH₃)₆]²⁺, [Co(H₂O)₆]²⁺ (both octahedral), and [CoCl₄]²⁻ (tetrahedral) are colored. One is pink, one is blue, and one is yellow. Based on the spectrochemical series and remembering that the energy splitting in tetrahedral complexes is normally much less than that in octahedral ones, assign a color to each complex.
Problem 82
- Complete the exercises below. Given the colors observed for VO₄³⁻ (orthovanadate ion), CrO₄²⁻ (chromate ion), and MnO₄⁻ (permanganate ion) (see Exercise 23.84), what can you say about how the energy separation between the ligand orbitals and the empty d orbitals changes as a function of the oxidation state of the transition metal at the center of the tetrahedral anion?
Problem 85
- Complete the exercises below. When Alfred Werner was developing the field of coordination chemistry, it was argued by some that the optical activity he observed in the chiral complexes he had prepared was due to the presence of carbon atoms in the molecule. To disprove this argument, Werner synthesized a chiral complex of cobalt that had no carbon atoms in it, and he was able to resolve it into its enantiomers. Design a cobalt(III) complex that would be chiral if it could be synthesized and that contains no carbon atoms. (It may not be possible to synthesize the complex you design, but we will not worry about that for now.)
Problem 88
- Complete the exercises below. Generally speaking, for a given metal and ligand, the stability of a coordination compound is greater for the metal in the +3 oxidation state rather than in the +2 oxidation state (for metals that form stable +3 ions in the first place). Suggest an explanation, keeping in mind the Lewis acid–base nature of the metal–ligand bond.
Problem 89
Problem 91a,d
The coordination complex [Cr(CO)6] forms colorless, diamagnetic crystals that melt at 90 °C
a. What is the oxidation number of chromium in this compound?
d. Write the name for [Cr(CO)6] using the nomenclature rules for coordination compounds.