Product Short Description: CHLOROAURIC ACID Product Description: Chloroauric acid refers to inorganic compounds with the chemical formula HAuCl ₄· ₓ. Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar [AuCl₄]⁻ anion. Often chloroauric acid is handled as a solution, such as those obtained by dissolution of gold in aqua regia.