Sulfides are more reactive than their oxygen-containing analogs, ethers, because they have an expanded octet and can form additional bonds with other atoms. They are particularly susceptible to oxidation.
Concept: Quick overview of oxidation.1m
Now we're going to explore the oxidation reactions of sulfides. Before we can talk specifically about sulfides, I think we need a little refresher on what oxidation is because it might have been a little while since you saw oxidation-reduction.
Just remember that oxidation is any reaction that's going to involve the increase in the oxygen content of a molecule. Now that doesn't mean that you're actually adding oxygens. It could just mean that you have more bonds to an oxygen.
This is a little table that I use during my oxidation-reduction lectures and what you should know about it is just you can see the pattern. As you move to the right, these molecules have more and more bonds to oxygen. If you think about it, a sulfide, what does a sulfide look like? We're going to look at it in a second, but it's a sulfur with zero oxygens on it. As we oxidize it, we would expect that we're going to get more and more bonds to oxygen. Cool.
Oxidation reactions involve an increase in the oxygen content of a molecule.
Concept: Reagents used to oxidize Sulfides.4m