Analogues of alcohols with it instead of oxygen are called thiols.
An oxyanion of this element is found in alum. Two compounds of this element form oleum. An oxyacid of this element is often formed with a vanadium-five-oxide catalyst. Analogues of alcohols with it instead of oxygen are called thiols. Two atoms of this element in nearby cysteine molecules form a "bridge." Its elemental form is a crumbly solid made of (*) eight-membered rings. A diprotic acid containing this element is formed by the contact and lead chamber processes. It is added to rubber in vulcanization. For 10 points, name this yellow element that forms a very poisonous, explosive, and rotten-egg-stinky gas with hydrogen.
An oxyanion of this element is found in alum. Two compounds of this element form oleum.
sulfur [accept S]