Insights into Ice Giant Interiors: High-Pressure C-N-H Phasee

The internal structure of ice giant planets, such as Neptune, is critical for understanding their geophysical properties and magnetic field generation. This study investigates the high-pressure chemistry of carbon, hydrogen, and nitrogen (CHN) compounds, revealing a novel CHxN2 phase formed at ~40 GPa. Using Raman spectroscopy and single-crystal X-ray diffraction, we characterize its crystal structure, demonstrating physical properties comparable to diamond and significantly surpassing those of ice. This diamond-like phase suggests the presence of a robust, nitrogen-rich component within Neptune's interior, influencing its density and layering. Our findings highlight nitrogen's pivotal role in shaping the chemical complexity of icy giants and provide new insights into their differentiated structures. We propose that this CNH phase may contribute to the dynamics of planetary magnetic fields through its impact on interior conductivity and convection. These results advance our understanding of icy giant planet formation and evolution, with implications for their geophysical and magnetic properties.