Ammonium tetrachloroaurate (AuCl4H6NO) is an inorganic compound composed of four elements: hydrogen, nitrogen, gold, and chlorine. This substance is usually found in the form of hydrates, which have the appearance of colorless to yellow crystals that can be dissolved in water and ethanol. Ammonium tetrachloroaurate is relatively stable in dry and anhydrous conditions, but it is easy to decompose in an environment with high humidity.

1. Catalyst: In organic chemistry, ammonium tetrachloroaurate can be used as a catalyst, especially in oxidation, reduction, and oxoalkylation reactions. It can promote the progress of chemical reactions, improve the selectivity and yield of reactions.

2. Materials science: In the field of materials science, ammonium tetrachloroaurate is used in the preparation of materials such as gold nanoparticles, gold films, and gold ceramics. These materials have a wide range of applications in electronics, catalysis, optics, and biomedicine.

3. Chemical research and laboratory work: Ammonium tetrachloroaurate is commonly used in chemical laboratories as a catalyst, coordination reagent, chlorine source and copper solvent for various chemical experiments and research.

4. Metal Coating and Gold Compound Preparation: In the electroplating industry, ammonium tetrachloroaurate is used for metal coating, especially in the electronics industry for the manufacture of semiconductor devices. It is also a raw material for the preparation of other gold compounds.

5. Analytical Chemistry: Ammonium tetrachloroaurate is used as an analytical reagent for gold in analytical chemistry for the determination of gold content in quantitative analysis.