Iron sulphide compound. Image 3 of 3. Iron sulphide is produced by heating a mixture of powdered iron and sulphur. It is a hard, non- magnetic compound. See image A500/593 for the two separate elements. Iron is a hard metallic metal and sulphur is a crumbly non-metallic non-metal. These elements can be used to demonstrate the difference between a physical and a chemical change. Mixing the two powders (see A500/594) is a purely physical change: the elements retain their properties and can be easily separated. A magnet could be used to pull away the iron, for instance. Forming iron sulphide is a chemical change, and the compound has different properties to its constituent elements.