Answer:
Oxygen and sulfur
Step-by-step explanation:
Alloys consist of metals fused together sometimes with additional components, such as carbon, to prevent metals from corrosion.
Oxygen and sulfur are two compounds consisting of non-metal atoms, O and S. Combining oxygen with sulfur would actually produce sulfur dioxide, a gas, in contrast to a metallic substance that is fused with some other metal or carbon.
That's the reason why combination of sulfur and oxygen wouldn't produce an alloy: it would produce a gas.