Nitric acid in aqua regia

Metallic technetium dissolves in oxidizing acids such as dilute or concentrated nitric acid, in aqua regia and in concentrated sulfuric acid. It is insoluble in hydrochlorid acid of any strength. The oxidizing dissoluion leads to colorless TcO. In oxygen at 500 °C technetium burns to TCjO, and in fluorine at... 

Noble metals, such as gold, platinum, palladium, rhodium and iridium are not attacked by nitric acid at ordinary temperatures. These metals, however, dissolve in aqua regia (3 1 HCl— HNOs mixture). Nitric acid in aqua regia oxidizes gold to Au , which readily combines with Cl to form soluble chloro-complex, AuClF. 

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