Image copyright Other Image caption The material has remarkable tensile stiffness

A material called carbyne could be stronger even than graphene or diamond, according to researchers who have calculated its properties.

A team says carbyne could have a range of remarkable properties, if it can ever be made in bulk - and some experts have doubted whether this is possible.

They have published their findings in the journal ACS Nano.

Carbyne is a chain of carbon atoms held together by double or alternating single and triple chemical bonds.

In their paper, Boris Yakobson and colleagues from Rice University in Houston show that carbyne's tensile strength - the ability to withstand stretching - surpasses that of "any other known material" and is double that of graphene, the flat sheet of carbon atoms that is often held up as a "supermaterial".

Scientists have already calculated that it would take an elephant balancing on a pencil to break through a sheet of graphene.

They also calculated that carbyne has twice the tensile stiffness of graphene and carbon nanotubes and nearly three times that of diamond.

It should display a number of other useful properties say the researchers. For example, it could be turned into a magnetic semiconductor (these are materials with electrical conductivity between that of a metal and an insulator like glass) and could be used as a sensor to detect twisting.

Some scientists have reported synthesising small amounts of carbyne in the lab, but it was thought to be extremely unstable. And some chemists have suggested that two strands coming into contact could react explosively.

"Our intention was to put it all together, to construct a complete mechanical picture of carbyne as a material," said Vasilii Artyukhov, also from Rice University.

"The fact that it has been observed tells us it's stable under tension, at least, because otherwise it would just fall apart."