What Happens When Gold Iodide Reacts With Other Chemicals?

Gold iodide (AuI3) is a yellowish-orange crystalline compound that is sparingly soluble in water. When gold iodide reacts with other chemicals, several possible reactions may occur depending on the specific reactant and conditions involved.

For example, when gold iodide is mixed with aqueous sodium sulfite (Na2SO3), it undergoes a redox reaction where the sulfur dioxide produced reduces the AuI3 to metallic gold (Au) and iodide ions (I-). This reaction can be written as:

AuI3 + 3 Na2SO3 + 3 H2O → Au + 3 SO42- + 6 Na+ + 3 I-

Similarly, gold iodide can also react with reducing agents such as hydrazine (N2H4) or sodium borohydride (NaBH4) to form gold nanoparticles (Au NPs) through a reduction process. In these cases, the AuI3 is reduced to Au^0, which then nucleates and grows into Au NPs. The reaction with sodium borohydride can be represented as follows:

AuI3 + 6 NaBH4 → Au + 3 NaI + 6 BH3 + 3 H2

On the other hand, gold iodide can also undergo substitution reactions with other halides, such as chlorine, bromine, or fluorine. For instance, when gold iodide is treated with chlorine gas (Cl2), it forms gold chloride (AuCl3) and iodine gas (I2) according to the following equation:

AuI3 + 3 Cl2 → AuCl3 + 3 I2

Overall, the chemical behavior of gold iodide depends on the nature of the reactants and the reaction conditions, but generally involves either redox or substitution processes.