Bond angle

[indigo bolt]

Isn't benzene bulkier than those 2 CH3 grps. to cause more bond angle ?

[bitter kernel]

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[fervent citrus]

Ok, I'm not one to say this usually, but I do recommend a tiny bit of research before you post a doubt. Google can do wonders.

[indigo bolt]

if benzene is bulkier so y the bond angle is lesser as compared to methoxymethane

[indigo bolt]

i searched but it contradicts the relation b/w the bulkiness and bond angle

[feral ledge]

The second one is an exception where the methyl groups are bulky which causes repulsion between them making the bond angle greater

But don't know the correct reason to explain first one

[indigo bolt]

what exactly is the exception u r talking about?

[real swan]

maybe resonance related reason

in phenol, 1 lone pair is in conjugation with the ring

in methoxymethane, there's 2 unscattered lone pairs

so i guess lonepair-lonepair repulsion causes the higher angle

[indigo bolt]

i took H2O for explaining my pt. if lone lone pair repulsion is greater so the effective bond angle b/w COC should decrease

[stoic snow]

Methoxymethane is some ether exception iirc

[real swan]

oh right

hmm

yeah this is weird

shouldn't the LP-LP interaction be greater than BP-BP interaction, reducing the ether angle instead of increasing it

@fervent citrus thoughts?

[fair tide]

i think it's smthing to do with their hybridisation. Like in methoxymethane, o is sp3 and lp strongly repel ch bond so more bond angle. In phenol o is partially sp2 due to reso toh ussey mabe lp repulsion reduces and bond angle becomes closer to tetrahedral

[fervent citrus]

Ok, not an amazing explanation on my behalf, and it's sort of unsatisfactory but the only thing I can think of is that in methoxymethane,

the compound exists as a superposition of its hyperconjugated structures right? So, there are net δ- charges on the carbons which are repelling each other, thereby increasing bond angle.

With phenol, resonating structures have no issue like this because on the other side, H doesn't have any electronic effects going on.

[indigo bolt]

a superposition of its hyperconjugated structures means?