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.)
An insulator is a material or method that restricts the transfer of either heat or electricity. Insulators are used to protect us from the dangerous effects of electricity flowing through conductors. Insulators are materials that have just the opposite effect on the flow of electrons.