Question

# The structure of capsaicin, the molecule that is responsible for the "heat" in chili peppers, is shown below.

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The structure of capsaicin, the molecule that is responsible for the "heat" in chili peppers, is shown below.

What are the approximate bond angles for the labeled angles? $$\displaystyle\beta=?,\delta,=?,\epsilon=?,\phi=?,\gamma=?$$

2021-03-03
$$\displaystyle\beta={120}$$. There are 3 bonds and no unshared pairs, so itsgeometry is trigonal
$$\displaystyle\delta={104.5}$$ There are 3 bonds and one unshared pair,resulting in a "squished" tetrahedral geometry
$$\displaystyle\epsilon={120}$$ Another trigonal geometry
$$\displaystyle\phi={109.5}$$ This is a standard tetrahedral geometry,occurring when carbon bonds to 4 atoms
$$\displaystyle\gamma={120.3}$$ 3 bonded atoms with no unshared pairs
Bonds X and W are the same length because of resonance. Electrons are shared equally among the 6 carbons in the ring.
Bond X is longer than bond Z because because bond Z is a doublebond, while X is closer to a 1.5 bond. Higher bond orderspull the atoms closer together.
Bond Y is longer than bond Z for essentially the same reason as above.