Sulfur was always with us, but we did not know what was going on!

The sequence over the years was Sulfur, S + Au, S + Au + 2 electron sensitization to simplify things. And, I didn't really cover this stuff in the book as it is supposed to be a "starter book". I guess I have to stop and re-write or do a 2nd edition!

But, there really is no one method to come up with one best solution. There are computer models to help predict what to do though.