Aqua regia
| Names | |
|---|---|
| IUPAC name
Nitric acid trihydrochloride | |
Other names
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| Identifiers | |
3D model (JSmol) |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| HNO3 + 3 HCl | |
| Appearance | Fuming liquid. Freshly prepared aqua regia is colourless, but it turns yellow, orange or red within seconds. |
| Density | 1.01–1.21 g/cm3 |
| Melting point | −42 °C (−44 °F; 231 K) |
| Boiling point | 108 °C (226 °F; 381 K) |
| Miscible | |
| Vapor pressure | 21 mbar |
| Hazards | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
Aqua regia (/ˈreɪɡiə, ˈriːdʒiə/; from Latin, "regal water" or "royal water") is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a fuming liquid. Freshly prepared aqua regia is colorless, but it turns yellow, orange, or red within seconds from the formation of nitrosyl chloride and nitrogen dioxide. It was so named by alchemists because it can dissolve noble metals such as gold and platinum, though not all metals.