Question
Answer the following about the structure of the iron pentacarbonyl metal complex, for 10 points each.
[10e] The carbonyl ligands bond to the iron with an antibonding orbital via this interaction, termed its namesake “backbonding.” P-orbitals overlap laterally in this interaction, which is found with a sigma bond in double bonds.
ANSWER: pi bond [accept pi backbonding]
[10m] Iron pentacarbonyl exhibits a low but present rate of Berry pseudorotation due to having this coordination geometry. In VSEPR theory, molecules with this geometry have three equatorial and two axial substituents.
ANSWER: trigonal bipyramidal
[10h] Iron pentacarbonyl obeys this statement governing the stability of transition metal complexes. Coordinatively saturated complexes satisfy this statement, but d8 complexes like Zeise’s salt are common counterexamples.
ANSWER: 18-electron rule
<Chemistry>
Summary
| 2024 ACF Winter at UC Berkeley | 2024-11-16 | Y | 3 | 20.00 | 100% | 100% | 0% |
| 2024 ACF Winter at Clemson | 2024-11-16 | Y | 8 | 13.75 | 75% | 63% | 0% |
| 2024 ACF Winter at Clemson | 2024-11-16 | Y | 8 | 18.75 | 25% | 100% | 63% |
| 2024 ACF Winter at Lehigh | 2024-11-16 | Y | 9 | 20.00 | 89% | 89% | 22% |
| 2024 ACF Winter at Northwestern | 2024-11-16 | Y | 9 | 17.78 | 78% | 89% | 11% |
| 2024 ACF Winter at Ohio State | 2024-11-16 | Y | 8 | 11.25 | 50% | 63% | 0% |
| 2024 ACF Winter at Online | 2024-11-16 | Y | 9 | 8.89 | 56% | 22% | 11% |
| 2024 ACF Winter at UBC | 2024-11-16 | Y | 3 | 20.00 | 100% | 100% | 0% |
| 2024 ACF Winter at Oxford | 2024-11-16 | Y | 11 | 11.82 | 55% | 55% | 9% |
| 2024 ACF Winter at Brandeis | 2024-11-16 | Y | 10 | 12.00 | 60% | 50% | 10% |
Data
| Boston University A | Boston University B | 10 | 10 | 0 | 20 |
| Bowdoin A | Amherst A | 10 | 0 | 0 | 10 |
| A Brandeis Supreme | Bowdoin B | 0 | 0 | 0 | 0 |
| Carabrandeis | Brandeises Brew | 10 | 10 | 0 | 20 |
| Northeastern A | Brown A | 0 | 0 | 0 | 0 |
| Williams A | Clark A | 10 | 10 | 0 | 20 |
| Diamond Brandeis | Yale B | 0 | 0 | 0 | 0 |
| MIT A | Tufts A | 10 | 10 | 0 | 20 |
| Tufts B | Yale C | 0 | 0 | 0 | 0 |
| Harvard A | Yale A | 10 | 10 | 10 | 30 |