Question 2.E.7

[Amir Bayat]

How can you calculate the bond angle values for part (c) of the question? The question is stated below.

(a) What is the shape of a thionyl chloride molecule, SOCl2? Sulfur is the central atom. (b) How many different OSCl bond angles are there in this molecule? (c) What values are expected for the OSCl and ClSCl bond angles?

I understand why the bond angle for OSCl must be greater than ClSCl, but how do you know the bond angle values?

[Katie Kyan 2K]

I don't think the question is asking you to calculate the exact bond angle. Knowing that the shape of SOCl2 is trigonal pyramid and that there are 4 regions of electron density involving one lone pair and 3 bonding pairs, the O-S-Cl bond angles are identical. Since SOCl2 has one lone pair, this lone pair decreases the angle of the O-S-Cl bond as it takes up a greater volume. Thus the angles are slightly less than 109.5 degrees which is the bond angle of a tetrahedral shaped molecule.

[LReedy_3C]

There is no calculation involved, just recognizing that because it is a central atom with 5 regions of electron density, it is a trigonal pyramidal shape, and so all the OSCL bonds would be about 109.5 degrees

[Ellis Song 4I]

Bond angles aren't something that we calculate, we just have to memorize them