Corrosive Substance - Common Types of Corrosive Substances

Common Types of Corrosive Substances

Common corrosive chemicals are classified into:

• Acids

• Strong acids — the most common are sulfuric acid, nitric acid and hydrochloric acid (H₂SO₄, HNO₃ and HCl, respectively).
• Some concentrated weak acids, for example formic acid and acetic acid
• Strong Lewis acids such as anhydrous aluminum chloride and boron trifluoride
• Lewis acids with specific reactivity, e.g. solutions of zinc chloride

• Bases

• Caustics or alkalis, such as sodium hydroxide (NaOH) and potassium hydroxide (KOH)
• Alkali metals in the metallic form (e.g. elemental sodium), and hydrides of alkali and alkaline earth metals, such as sodium hydride, function as strong bases and hydrate to give caustics
• Extremely strong bases (superbases) such as alkoxides, metal amides (e.g. sodium amide) and organometallic bases such as butyllithium
• Some concentrated weak bases, such as ammonia when anhydrous or in a concentrated solution

• Dehydrating agents such as concentrated sulfuric acid, phosphorus pentoxide, calcium oxide, anhydrous zinc chloride, also elemental alkali metals
• Strong oxidizers such as concentrated hydrogen peroxide
• Electrophilic halogens: elemental fluorine, chlorine, bromine and iodine, and electrophilic salts such as sodium hypochlorite or N-chloro compounds such as chloramine-T; halide ions are not corrosive, except for fluoride
• Organic halides and organic acid halides such as acetyl chloride and benzyl chloroformate
• Acid anhydrides
• Alkylating agents such as dimethyl sulfate
• Some organic materials such as phenol ("carbolic acid")