What is the geometry of the oxygen in CH3OCH3?

1 Answer
Dec 24, 2016

The electronic geometry around is oxygen in #H_3C-O-CH_3# is #"TETRAHEDRAL"# to a first approximation.........

Explanation:

Why? Well, there are #2xxO-C# bonds, and 2 oxygen-centred lone pairs of electrons. The most stable geometry for the electron pairs, bonding and non-bonding is a tetrahedron, a prediction of #"VSEPR"#. Because the oxygen-centred lone pairs are close to the oxygen (and not bound to a neighbouring atom), these tend to compress the #/_C-O-C# bond angle to give a value of #105^@# rather than #109.5^@#.

But we describe molecular geometry on the basis of bound atoms, not lone pairs. #"Dimethyl ether"# is bent around oxygen, a precise analogue of water. Agree? What about #H_3C-S-CH_3#?