Chloroauric acid (hydrogen tetrachloroaurate(III)) is a gold compound used to prepare most other gold compounds.

Some properties:

Appearance: yellow-orange needle-like crystals.
Solubility: readily soluble in water, as well as in alcohols, ethers, esters, ketones, acetonitrile.
Preparation: obtained by reacting metallic gold with aqua regia, hydrochloric acid, or a hydrochloric acid solution.
Applications: used to form simple salts, precipitate large cations, perform ligand substitution reactions, as well as for redox and extraction processes.
Formula: H[AuCl4]·nH2O, where n = 3 or 4.