While diamonds are renowned for their extreme hardness and resistance to most chemicals, they are not entirely indestructible by acids. The exact answer is that hot concentrated nitric acid or perchloric acid can dissolve diamonds.
Diamond, essentially a crystalline form of carbon, is highly unreactive under typical conditions. This is why it withstands exposure to many common acids and bases. However, under specific, harsh conditions involving strong oxidising agents, the carbon structure can be broken down.
As noted in materials science discussions, it won't dissolve in most acids, with the exception of oxidising acids like hot concentrated nitric or perchloric acid.
The Role of Oxidising Acids
The key to dissolving diamond with these specific acids lies in their powerful oxidising properties. At high temperatures and concentrations, nitric (HNO₃) and perchloric (HClO₄) acids can provide enough energy and reactive oxygen species to attack the robust carbon-carbon bonds within the diamond lattice. This process essentially oxidises the carbon atoms, converting them into gaseous carbon oxides (like CO₂), which allows the diamond to break down or "dissolve" over time.
- Why hot and concentrated? The reaction requires significant energy input (heat) to overcome the strong bonding in the diamond structure. High concentration ensures a sufficient supply of the reactive acid molecules.
Most other acids, including common ones like hydrochloric acid (HCl) or sulfuric acid (H₂SO₄) when not acting as powerful oxidisers, lack the necessary oxidising strength to react with diamond's stable carbon structure.
Key Takeaways:
- Diamonds are highly resistant to most acids.
- Specific oxidising acids can dissolve diamond under harsh conditions.
- The acids capable of this are hot concentrated nitric acid and perchloric acid.
- The process involves oxidation of the carbon atoms.
In summary, while you cannot dissolve a diamond with common household acids, powerful oxidising acids like hot concentrated nitric or perchloric acid are exceptions to diamond's general chemical resistance.