Sulfur, by itself, doesn't have a specific oxidation number. Oxidation numbers are assigned to atoms in compounds or ions. Sulfur can exhibit a variety of oxidation numbers depending on the compound it's in. Here are some examples:

* Elemental Sulfur (S): Oxidation number = 0

* Sulfide ion (S²⁻): Oxidation number = -2

* Sulfur dioxide (SO₂): Oxidation number = +4

* Sulfur trioxide (SO₃): Oxidation number = +6

* Sulfuric acid (H₂SO₄): Oxidation number = +6

* Hydrogen sulfide (H₂S): Oxidation number = -2

To determine the oxidation number of sulfur in a compound:

1. Assign oxidation numbers to other elements in the compound based on their usual oxidation states. (e.g., Oxygen is usually -2, Hydrogen is usually +1)

2. The sum of all oxidation numbers in a neutral compound must equal zero.

3. The sum of all oxidation numbers in a polyatomic ion must equal the charge of the ion.

For example, in sulfur dioxide (SO₂), oxygen has an oxidation number of -2. Since there are two oxygen atoms, the total negative charge is -4. To balance this, the sulfur must have an oxidation number of +4.