Iron(II) sulfide or ferrous sulfide (Br.E. sulphide) is a chemical compound with the formula FeS. In the oil/gas industry, iron sulfides are often present in a sour system due to reaction between corrosion products and hydrogen sulfide.
A material that conducts (see conduction) electricity poorly or not at all. If a voltage is applied to a dielectric, the atoms in the material arrange themselves in such a way as to oppose the flow of electric current. Glass, wood, and plastic are common dielectrics. (See insulator.)
How effective a dielectric is at allowing a capacitor to store more charge depends on the material the dielectric is made from. Every material has a dielectric constant Îº. This is the ratio of the field without the dielectric (Eo) to the net field (E) with the dielectric: Îº = Eo/E.