* -tion: This is the most common spelling, found in words like "action," "motion," "attention," "creation."
* -sion: This spelling is used in words like "tension," "explosion," "decision," "permission."
* -cian: This spelling is used in words like "musician," "magician," "politician."
It's important to note that these are just general guidelines. Some words may have different spellings for this sound, and you may need to look them up individually.