Citric anhydride is not a stable compound and is not commonly used in commercial or industrial applications due to its instability and inability to be stored effectively. It is not found in nature. In contrast, citric acid is widely utilized as a preservative, pH adjuster, and solubilizing agent in the food, beverage, cosmetics, and pharmaceutical industries. While citric anhydride may theoretically serve as a reactive intermediate in organic synthesis, such as in esterification or acylation reactions, its practical applications are limited by its instability, and it is not available as a standard reagent.