[furaniki18]

among phenol, methanol and dimethyl ether which has the largest bond angle and which the lowest?
if i see the hybridisation of oxygen atom in all the three compounds, it is sp³ hybridised which means that all the three compounds have tetrahedral geometry, then why do they have different bond angles about oxygen atom?

[discodermolide]

among phenol, methanol and dimethyl ether which has the largest bond angle and which the lowest?
if i see the hybridisation of oxygen atom in all the three compounds, it is sp³ hybridised which means that all the three compounds have tetrahedral geometry, then why do they have different bond angles about oxygen atom?

Depends on the steric repulsion of the neighboring groups to the oxygen lone pairs.

[orgopete]

I think this is a VESPR type of question. In methane, the bond angles are all 109.5°, but in ammonia 107°, and water 105° (or something like that). They are all sp3, so that doesn't explain the difference. It is usually explained that the non-bonded electrons of water and ammonia take up more room and contract the HXH bond angle. I would argue that there is a corollary to this and it is the protons of X-H bond pull electrons away and reduce the size of the electron pair and then enables the bond pair expansion. If this were true, then you could argue the smallest electron pairs should have the smallest bond angle.