Aluminum tripolyphosphate is an inorganic compound with the general formula AlH₂P₃O₁₀·2H₂O. It is a white, odorless, crystalline powder that is insoluble in water but soluble in strong acids and alkalis. Its structure is based on a network of phosphate groups, which is key to its functional properties. Its primary and most significant industrial application is as a non-toxic, environmentally friendly anti-corrosive pigment in primers and coatings for metals, particularly steel and aluminum. It functions by reacting with metal ions to form a stable, insoluble phosphate layer that passivates the metal surface, effectively inhibiting corrosion. This makes it a leading alternative to traditional chromate and lead-based pigments. Additionally, it finds use as a catalyst or catalyst support in certain organic synthesis reactions due to its acidic and porous nature. Other notable applications include its use as a flame retardant additive in polymers and plastics, where it promotes char formation, and as a component in dental cements and adhesives. It is generally considered to have low toxicity, contributing to its preference in eco-friendly formulations.