 Iron(II) sulfide has its own distinct properties such as melting point and solubility, and the two elements cannot be separated using normal mechanical processes; a magnet will be unable to recover the iron, since there is no metallic iron present in the compound.While the term "chemical substance" is a precise technical term that is synonymous with "chemical" for chemists, the word "chemical" is used in general usage in the English speaking world to refer to both (pure) chemical substances and mixtures (often called "compounds"), and especially when produced or purified in a laboratory or an industrial process.In other words, the chemical substances of which fruits and vegetables, for example, are naturally composed even when growing wild are not called "chemicals" in general usage.