chlorination with SO2cl2

If you are planning to use SO₂Cl₂, my suggestion is to distill it shortly before use.  There was a low boiling impurity, at least the material that I had.  If this is purely a hypothetical exercise, then please excuse the intrusion.

I think it is vise versa. SO₂Br₂ is not existing, so NBS can only be used. For chlorination SO₂Cl₂  is existing and can be used. NCS is also possible.

yes ncs can also be used but not a best choice ....my question is why it's not a best choice .