Isodesmic Equations
Question 1
For the following reactions, would you expect the product to be more or less thermodynamically stable than the reactants, based on average bond energies:
- SbCl3 + F2 → SbF3 + Cl2 [Solution]
- P(CH3)3 + S8 → S=P(CH3)3 [Solution]
- H2CO3 → CO2 + H2O [Solution]
Question 2
For the following reactions, which product would be expected to form (or neither):
- P4 + Cl2 → PCl3 or PCl5 ? [Solution]
- HCCH + Br2 → HBrCCBrH or HBr2CCBr2H ? [Solution]
- CN- + O2 → OCN- or CNO- (linear) ? [Solution]
CGMT Theory
Question 1
Would the following Compounds be expected to have planar or trans-bent geometries?
- H2CCH2 [Solution]
- H2SiSiH2 [Solution]
- H2CSiH2 [Solution]
Fragment | Singlet-Triplet Gap (kJ mol-1) |
CH2 | -38 |
SiH2 | 88 |
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Bond | Bond Energy (kJ mol-1) |
CC(σ) | 346 |
SiSi(σ) | 222 |
CSi(σ) | 300 |
CC(π) | 295 |
SiSi(π) | 120 |
CSi(π) | 139 (est.) |
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