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Which chemicals can dissolve gold?

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A diagram showing the periodic table entry for gold, with the symbol Au, atomic number 79, atomic weight 196.96657, electron configuration, and labels for its properties as a solid transition metal with a face-centered cubic crystal structure. — gold The precious metal gold is a chemical element with the symbol Au. Its square on the periodic table details some of its properties, including its atomic weight, atomic number, and crystal structure.

Gold is a noble metal known for its chemical inertness, meaning it does not easily react with most substances. However, it can be dissolved through specific chemical processes:

Aqua Regia: This highly corrosive mixture of concentrated nitric acid and hydrochloric acid is famously capable of dissolving gold.12
Cyanide Solutions: In the presence of oxygen or hydrogen peroxide, gold dissolves in alkaline cyanide solutions. This process, known as cyanidation, is the primary method used for recovering gold from low-grade ores.32
Mercury: Elemental gold is soluble in mercury. When brought into contact, they form an alloy known as amalgam. While historically significant for gold recovery, the use of mercury is now strictly limited due to the severe environmental and health hazards associated with mercury poisoning.4

It is important to note that because of the significant risks to human health and the environment, the use of substances like mercury and cyanide requires rigorous safety protocols and ethical management to prevent contamination and harm.43