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Chemistry

Water can turn into a superacid that makes diamonds

Simulations suggest that water can become a superacid under extremely high heat and pressure conditions. This may also explain how planets like Uranus and Neptune get diamond rain

By Jeremy Hsu

24 March 2025

Superacids can turn carbon molecules into diamonds

Sefa Kart/Alamy

Water may transform into a superacidic fluid under extreme heat and pressure. These conditions are found only in Earth’s interior, within icy planets like Uranus and Neptune – and possibly in controlled laboratory experiments.

“Under immense pressures and temperatures, water exhibits a remarkable property – it becomes an exceptionally potent acid, also known as a ‘superacid’, which can be billions or even trillions of times stronger than sulphuric acid,” says Flavio Siro Brigiano at Sorbonne University in France.

This…

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