Anhydrides are chemical compounds formed by the removal of water from an acid. They can be classified into two main types: organic and inorganic. Organic anhydrides, such as acetic anhydride, are derived from carboxylic acids, while inorganic anhydrides, like sulfur trioxide, are derived from mineral acids. Anhydrides are often used in various chemical reactions, including the synthesis of esters and amides. In addition to their role in organic synthesis, anhydrides can also act as dehydrating agents. This property makes them useful in industrial applications, such as the production of plastics and pharmaceuticals. However, some anhydrides can be corrosive and require careful handling to ensure safety.