(3-Aminopropyl)trimethylsilane hydrochloride is an organosilane compound with the molecular formula C?H??ClNSi. This hydrochloride salt derivative of (3-aminopropyl)trimethylsilane is widely used as a coupling agent, surface modifier, and intermediate in organic and materials chemistry. Its reactive primary amine group enables covalent bonding with various substrates, while the hydrolyzable trimethylsilyl moiety facilitates silanization processes. The compound is particularly valuable in surface functionalization, adhesion promotion, and the synthesis of hybrid organic-inorganic materials. Its stability in hydrochloride form enhances handling and storage compared to the free amine. Applications include coatings, nanocomposites, and biomedical materials where controlled surface properties are critical. The product is typically supplied as a white crystalline powder with high purity.