Scientists have discovered a new state of physical matter in which atoms can exist as both 

solid and liquid simultaneously.

Until now, the atoms in physical material were understood to exist typically in one of three 

states—solid, liquid or gas. Researchers have found, however, that some elements can, w

hen subjected to extreme conditions, take on the properties of both solid and liquid states.

Applying high pressures and temperatures to potassium—a simple metal—creates a state in 

which most of the element's atoms form a solid lattice structure, the findings show. However, 

the structure also contains a second set of potassium atoms that are in a fluid arrangement.

Under the right conditions, over half a dozen elements—including sodium and bismuth—are 

thought to be capable of existing in the newly discovered state, researchers say.

Until now, it was unclear if the unusual structures represented a distinct state of matter, or 

existed as transition stages between two distinct states.

A team led by scientists from the University of Edinburgh used powerful computer simulations 

to study the existence of the state—known as the chain-melted state. Simulating how up to 

20,000 potassium atoms behave under extreme conditions revealed that the structures 

formed represent the new, stable state of matter.

Applying pressure to the atoms leads to the formation of two interlinked solid lattice structure

s, the team says. Chemical interactions between atoms in one lattice are strong, meaning 

they stay in a solid form when the structure is heated, while the other atoms melt into a liquid 

state.