2020/11/26 by Lewis J. Conway, Chris J. Pickard, Conway, Lewis J. +3
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Advanced Chemical Physics Studies #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #High-pressure geophysics and materials #Inorganic Fluorides and Related Compounds #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2011.13285
openalex publication_date 2020/11/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The make-up of the outer planets, and many of their moons, are dominated by matter from the H-C-N-O chemical space, commonly assumed to originate from mixtures of hydrogen and the planetary ices H2O, CH4, and NH3. In their interiors, these ices experience extreme pressure conditions, around 5 Mbar at the Neptune mantle-core boundary, and it is expected that they undergo phase transitions, decompose, and form entirely new compounds. In turn, this determines planets' interior structure, thermal history, magnetic field generation, etc. Despite its importance, the H-C-N-O space has not been surveyed systematically. Asked simply: at high-pressure conditions, what compounds emerge within this space, and what governs their stability? Here, we report on results from an unbiased crystal structure search amongst H-C-N-O compounds at 5 Mbar to answer this question.