Kryptonite – which incited so much fear in Superman and his race – may no longer be the stuff of fiction, as scientists claim they they’ve got the formula for it.

Theoretical chemists from the Polish Academy of Sciences’ Institute of Physical Chemistry have learned a way to synthesize the first binary compound of krypton plus oxygen, called a krypton oxide. They found that today’s laboratories can produce this substance under the necessary outstandingly high pressure.

Krypton, a gas which the fictional planet Krypton was named after, is deemed incapable of creating stable compounds of chemicals. The new research, however, showed it is possible to synthesize a new material where krypton atoms would bond chemically to a different element.

Author Patrick Zaleski-Ejgierd clarified that they are predicting a compound combining krypton and oxygen, not nitrogen – hence it should be kryptoxide instead of kryptonite as stated in the popular comic book. This mean Superman can take it easy in the meantime.

The team’s krypton monoxide (KrO) is likely nonexistent in nature.

“According to current knowledge, the deep interiors of planets are the only place where there is sufficient pressure for its synthesis. Oxygen does not exist there, nor does krypton," he further explains (PDF).

Krypton compounds – small, single, and linear molecules of the hydrogen-carbon-krypton-carbon-hydrogen kind – were laboratory-produced using cryogenics. The researchers used genetic models and algorithms based on the density functional theory, a fundamental part of chemical molecular studies.

The team found that KrO crystals will form at a pressure between the 3 and 5 million atmosphere range – a high pressure yet one that can be attained in labs today when one squeezes samples in diamond anvils.

According to calculations, the crystals exhibit semiconductor qualities, are dark, and have a relatively poor transparency.

The chemists also stumbled on a second and quite less stable krypton compound called tetroxide KrO₄, estimated to have metallic properties, a simpler structure, and possible at a given pressure beyond 3.4 million atmospheres.

Once they form, the two types of krypton oxide crystal would likely exist in a pressure lower than required for them to form. However, pressure on the planet is low enough for the crystals to rapidly degrade.

Zaleski-Ejgierd dubbed reactions at such high pressure as extremely exotic chemistry.

“In those cases, even methods of theoretic description fail!” he says. However, it highlights the thrill of performing the first until the last step in synthesizing.

The study was published in the journal Scientific Reports.