Unbelief

Colossians 3:6 For which things’ sake the wrath of God cometh on the children of disobedience: KJV 

Colossians 3:6 For which things the wrath of God cometh upon the children of unbelief,  Douay Rheims

Colossians 3:6 for which things the wrath of God came on the sons of unbelief; Wycliffe

The key word Unbelief appears 20 times and Disobedience appears 19 times with Disobey once.  Unbelief and Disobedience are two very different words.  Unbelief means you don't believe in God. Disobedience means you are not obeying, God, in this instance.  

Now, Paul understood when he was talking to the church at Colosse, these were people were either new in faith or were not part of the Jewish religion.  In essence, they were unbelievers but they were also disobedient because of how they lived their lives apart from God.  Both words correctly describe the early church at Colosse they were unbelievers who walked in disobedience by living a life outside of Jesus. 

The Lord wanted you to get the backdrop of this part before moving forward with what Paul felt the Church at Colosse and the early Christians were doing apart from their belief and obedience to Jesus Christ and the Word of God.  

There is one other word which is different, sons and children.  Again, taken in context Paul is writing to the early Church Christians which would be new to Christ and how to be a child or a son (daughter) of God.  Our key word unbelief is probably a better explanation because you cant be disobedient to something you do not follow or obey when it comes to belief in Christ.  Paul has to remind them about their unbelief and disobedience in the very next verse:

 Colossians 2:7 In the which ye also walked some time, when ye lived in them.  

As strange as this sounds, you can have unbelief and obey God and you certainly can have belief and disobey God.