Islamic State is reportedly on a wild-goose chase for a substance that doesn’t exist.

There’s just one problem: It’s not real. It’s the stuff of doomsday-dreamers.

Despite its more than dubious existence, the red mercury myth continues to endure and the Islamic State appears to be the latest to join the wild goose chase.

Stories of the fabled substance first appeared in Russian and Western media outlets in the late 1980s at the end of the Cold War. The references to the chemical were vague but promoted its fundamental importance in creating a powerful nuclear bomb.

Shortly after the stories appeared, so did a scourge of wishful buyers. Although little was actually known about it, red mercury became hot property on the black market full of aspiring bomb makers. It quickly developed a reputation of its own and those selling it allowed the buyer to infer their own ideas of its power — and they charged an astronomical price for the privilege.

It promised to compress fusion materials to detonate a nuclear device as small as a tennis ball. But whenever dealers were caught with the substance, it invariably turned out to be something far more innocuous.

In reality, as TheNew YorkTimesput it, red mercury was no more than “the gullible man’s shortcut to a nuclear bomb.”

Red mercury, as it turns out, was more of a red herring.

Many who work in intelligence believe the stories were planted as a means to flush out rogue terrorists and waste their time. Another theory holds that red mercury might have been a Soviet code name for another substance — possibly lithium-6 — a controlled material with an actual use in nuclear weaponry.

There is no verified reason as to why the stories first appeared.

Despite its widely discredited existence, a comprehensive investigation by the Times reported an Islamic State commander known as ‘The Crocodile’ was trying to source the elusive substance for the militant group’s sadistic ventures.

A man identified as Abu Omar living in the Syrian town of Tal Abyad near the Turkish border operates as an informant and procurer of all things sinister for rebel groups, including IS.

He said the group’s militant commander was willing to pay up to $US5.5m ($A7.64m) for each unit of red mercury that matched a set of photographs he sent to Mr Omar over messaging service WhatsApp.

They were shopping for red mercury.

Red mercury is thought to be a ‘hoax’ substance vital in nuclear weaponry.Source:News Limited

The most confounding thing about the mythical substance is its enduring reputation as a genuine weapon of mass destruction.

Anyone with access to the internet can quickly see the immense scepticism surrounding the material. Wikipedia describes it as a “hoax substance”.

Debate and speculation over the substance roared in the 90s. A 1992 report in the New Scientist compiled by researchers at the Los Alamos National Laboratory attested to the lofty mystic of the material peddled by war mongering demagogues.

“You want a short cut to making an atomic bomb? You want the key to Soviet ballistic missile guidance systems? Or perhaps you want the Russian alternative to the anti-radar paint on the stealth bomber? What you need is red mercury,” the report said.

For any myth to persist it requires the aid of some credible champions. For red mercury, there has been no shortage of such characters.

American physicist Samuel T Cohen is perhaps the most notable. Known as the inventor of the neutron bomb he went to his death bed believing in the power of red mercury.

In a particular edition of his autobiography posted online, he claimed it was manufactured by ‘‘mixing special nuclear materials in very small amounts into the ordinary compound and then inserting the mixture into a nuclear reactor or bombarding it with a particle-accelerator beam.’’

While most of the rumours have manifested in the third world, western media outlets have also been complicit in their survival. The UK’s Channel 4 added to the hype with two documentaries called Trail of RedMercury and Pocket Neutron.

In 2004 a group of British men were arrested for trying to buy a kilo of red mercury for £300,000 ($A63,7260). During the trial the jury was told “that whether red mercury does or does not exist is irrelevant.”

The case prompted the International Atomic Energy Agency to issue a statement dismissing claims that the substance was real. “Red mercury doesn’t exist,” it said.

“The whole thing is a bunch of malarky.”

Yet still, it remains stubbornly present on the shopping list of terrorists around the world.

US diplomatic cables published by Wikileaks in 2010 and 2011 showed concern voiced by the Sri Lankan government in 2006 to the American embassy in Colombo that the Tamil Tigers were trying to obtain the material.

‘‘Red Mercury is a well-known scam material,’’ a state department nonproliferation official told the embassy, ‘‘there is nothing to be concerned about.’’

In 2013 the Cihan News Agency, one of Turkey’s largest news agencies, casually reported on the properties of the substance in a case in which three men were arrested for possessing “a red-mercury rocket warhead”.

According to TheNew York Times article, pictures of the rocket began circulating on social media shortly afterwards. The online images held an exact likeness to the WhatsApp photos sent to Abu Omar by the Islamic State commander.

As for Mr Omar and his IS associates, just like their anti-western ideology, their belief in red mercury seems to be unshakable.

When Times journalist CJ Chivers presented him with evidence that the chemical was a hoax, he was undeterred in his given mission to procure it.

‘‘I have seen it with my own eyes,’’ he said before recounting a curious story of a test conducted years earlier by IS militants with what he called liquid red mercury.

Effort to dispel the rumours such as the Campaign Against Red Mercury have had success in addressing the danger of the persistent rumours.

But to Islamic State militants, such projects are merely deemed to be the work of non believers.