Corrosive substance or slowly over days or years, e.g. the rusting of iron in a bridge. Sometimes the word caustic is used as a synonym for "corrosive", but "caustic" refers only to strong bases, particularly alkalis, and not to acids, oxidizers, or other non-alkaline corrosives. At low concentrations, a corrosive substance is called an irritant, and its effect on living tissue is called irritation. At high concentrations, a corrosive substance causes a chemical burn, a distinct type of tissue damage. Corrosives are different from poisons in that corrosives are immediately dangerous to the tissues they contact, whereas poisons may have systemic toxic
Chemical property can be discerned without changing the substance's structure. However, for many properties within the scope of physical chemistry, and other disciplines at the boundary between chemistry and physics, the distinction may be a matter of researcher's perspective. Material properties, both physical and chemical, can be viewed as supervenient; i.e., secondary to the underlying reality. Several layers of superveniency are possible. Chemical properties can be used for building chemical classifications. They can also be useful to identify an unknown substance or to separate or purify it from other substances. Materials science will normally consider the chemical properties of a substance to