Gold monoiodide is the inorganic compound of gold and iodine with the formula AuI. It can be synthesized by dissolving gold powder in an aqueous solution of iodine and potassium iodide. With Lewis bases, AuI reacts to give numerous complexes.
Gold monoiodide can be obtained by reacting a tetrachloridoauric acid solution with potassium iodide. It is also possible to produce it by reacting gold and iodine in a protective atmosphere at around 390 ðC.
Gold monoiodide is a yellow, crystalline powder that gradually decomposes upon contact with water, humidity or light. It has a tetragonal crystal structure with the space group P4<sub>2</sub>/ncm (space group no. 138), a = 4.359 ÃÂ , c = 13.711 ÃÂ .