How do pi bonds affect bond angle?
1 Answer
You may be referring to a situation where we are comparing the molecular geometry of two molecules where one has a higher bond order on certain bonds and the other doesn't.
For example, let's compare the bond angles of
#"O"-"Cl"-"O"# bond angle:#115.30^@# (#"ClFO"_3# )#"H"-"C"-"H"# bond angle:#109.47^@# (#"CH"_4# )#"H"-"N"-"H"# bond angle:#106.67^@# (#"NH"_3# )
Now, why the decrease going from
METHANE BOND ANGLE
Let's start from
AMMONIA BOND ANGLE
When we move from
Notice how there is a lone pair of electrons on
PERCHLORYL FLUORIDE BOND ANGLE
When we move from
Notice how we went from having four single bonds to one single bond and three double bonds. The bonding pair in each double bond has greater electron density than a single bond. The bonding pairs can repel each other to a greater extent because it is easier for electrons to instantaneously repel each other when they often appear near each other. Hence, the additional
Additionally, you have the fluorine, which is the most electronegative atom on the molecule, and that means it draws electron density towards it.
That polarizes the molecule upwards through the
If we suppose the electron density on each
That, along with the presence of the additional