FES (Ayase Kishimoto), a fictional singer from Chaos;Head anime series and alias of Yui Sakakibara for her songs from Chaos;Head and Steins;Gate anime series
Iron(II) sulfide or ferrous sulfide (Br.E. sulphide) is a chemical compound with the formula . In practice, iron sulfides are often iron-deficient non-stoichiometric. Powdered iron sulfide is pyrophoric (ignites spontaneously in air).