Murexide is a chemical compound known by its systematic name, ammonium purpurate. It is a crystalline substance with a distinct purple color, often used as an indicator in analytical chemistry. Murexide has a wide range of applications due to its ability to change color depending on the pH level of the solution it is added to. In its natural state, Murexide appears as purple crystals, but when it reacts with acidic or basic substances, it changes color, making it a valuable tool for determining the endpoint of chemical reactions.

One of the primary uses of Murexide is as an indicator in complexometric titrations. In these titrations, Murexide is added to a solution containing metal ions, and its color change helps determine the point at which all the metal ions have formed stable complexes with a chelating agent. This color shift from purple to a pink or violet hue is easily visible and signifies the end of the titration. Additionally, Murexide finds application in the analysis of calcium and magnesium ions in water samples and is employed in the production of ink, particularly purple and violet ink varieties.