Cobalt sulfide is a mineral that combines atoms of cobalt and sulfur. Its general chemical formula is CoxSx, and its most commonly found compounds are CoS2, Co3S4 and Co9S8.
Cobalt sulfide is used as a catalytic agent in the production of refined petroleum products using the process of hydrodesulfurization. Depending on its structure, cobalt sulfide may also be called sycoporite, cobalt(II) sulfide, sulfanylidenecobalt and cobalt monosulfide. A molecule of cobalt sulfide with one atom of each element has a molar mass of about 90.99 grams per mole. It is soluble in water and somewhat soluble in acid. Depending on its form, it may appear as either a black solid or a red-and-gray-colored crystal.