There's a bit of a misunderstanding in your question. "Iron sulfur" refers to a compound, not an element.

Here's why:

* Iron is an element with the symbol Fe and atomic number 26.

* Sulfur is an element with the symbol S and atomic number 16.

When iron and sulfur combine, they form compounds like iron sulfide (FeS). Compounds don't have individual atomic numbers, but rather are made up of elements with specific atomic numbers.