An unusually complex form of one of the most abundant chemical elements on Earth was first discovered in the laboratory.
The researchers created a crystallized version of nitrogen, which is the main constituent of air under normal conditions, exposing it to extreme pressures and temperatures.
The study shows for the first time that simple molecular elements can have complex structures at high pressures.
There might be similar studies in other elements, say researchers.
An international team of scientists, led by the University of Edinburgh, used a high-pressure diamond anvil to press tiny amounts of nitrogen at a pressure of half a million times that of the earth's atmosphere while being heated to about 500 ° C.
They then used a special x-ray technology to take a picture of the resulting crystals and were surprised when the nitrogen formed a complicated array of dozens of molecules.
The team had expected to uncover a much simpler structure.
Their results solve speculations about the structure of this form of nitrogen, known as ι-N2. It was discovered 15 years ago, but its structure was previously unknown.
Computer simulations of the new structure have provided valuable insights and found them surprisingly stable.
The study, published in Nature Communicationswas carried out in collaboration with the European Synchrotron Radiation Facility in France and with researchers in China. It was supported by the Research Council Engineering and Physical Sciences.
Robin Turnbull of the University of Edinburgh's Faculty of Physics and Astronomy, who led the study, said, "We hope that these results will further investigate why relatively simple elements should form such complex structures – it is important that we continue promising new elements seek new lines of scientific investigation. "
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Robin Turnbull et al., Unusually complex phase of dense nitrogen under extreme conditions Nature Communications (2018). DOI: 10.1038 / s41467-018-07074-4