What is the electronic and molecular geometry of #"dimethyl ether"#?
We deal with
And thus, to a first approx.,
Because oxygen bears 2 lone pairs, which, as non-bonding entities, tend to lie closer to the oxygen atom, the low pairs may tend to compress
I always think about what molecule looks similar, and remember its molecular and tetrahedral geometry.
- the central oxygen is analogous to the oxygen in water if the two
#"CH"_3#fragments are replaced with #"H"#atoms. Water is bent, with a tetrahedral electron geometry, and thus has a VSEPR-predicted bond angle of #bb(109.5^@)#.
Naturally, that angle is not strictly correct (it is actually
#104.4776^@#in water), due to the lone pair crunching the molecule together, but given you are asked for the IDEAL bond angle, that's what you'll have to type in regardless.
- for one choice of carbon atom in this molecule, if you change the remaining
#"OCH"_3#to #"H"#, then it looks just like methane, #"CH"_4#. Therefore, the atom has around it a tetrahedral electron geometry, and a #bb(109.5^@)#IDEAL angle as well...
Or, if you just counted electron groups around both central atoms (