алт боловсруулах мөнгөн ус сүсэг aqua regia
Niobium and tantalum are resistant to all acids, including aqua regia. This handbook 1 gives an overview of which noble metals are attacked by aqua regia: Niobium is reported a corrosion rate of 0.025mm/yr in aqua regia at 328.15 K. Gold is attacked by aqua regia.