Hydrogen cyanide and hydrocarbons mix on Titan
Journal article, 2025
This work reveals a striking exception to the well-established rule in chemistry that polar and nonpolar compounds do not spontaneously mix: insertion of methane, ethane, and other small hydrocarbons into the crystal lattice of hydrogen cyanide (HCN), a highly polar molecule. By mixing these components at cryogenic temperatures, we can observe distinct shifts in vibrational modes using Raman spectroscopy. Our computational predictions confirm that cocrystal structures of HCN and ethane, which match our experimental vibrational shifts closely, are thermodynamically and kinetically stable. Given that methane, ethane, and HCN are major components of the atmosphere and surface of Saturn’s moon Titan—where they play key roles in shaping chemistry, weather, and landscape—our findings may prove instrumental for explaining Titan’s chemical and geological evolution.
hydrogen cyanide
cocrystals
quantum chemistry
planetary science
astrochemistry
Author
Fernando Izquierdo Ruiz
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Complutense University
Morgan L. Cable
California Institute of Technology (Caltech)
Robert Hodyss
California Institute of Technology (Caltech)
Tuan H. Vu
California Institute of Technology (Caltech)
Hilda Sandström
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Alvaro Lobato Fernandez
Complutense University
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Martin Rahm
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Proceedings of the National Academy of Sciences of the United States of America
0027-8424 (ISSN) 1091-6490 (eISSN)
Vol. 122 30 e2507522122Nya material med relevans för livets ursprung och planetforskning
Swedish Research Council (VR) (2016-04127), 2017-01-01 -- 2020-12-31.
Computational Astrobiology: The Rise of Macromolecules
Swedish Research Council (VR) (2020-04305), 2021-01-01 -- 2024-12-31.
Subject Categories (SSIF 2025)
Theoretical Chemistry
Physical Chemistry
DOI
10.1073/pnas.2507522122
PubMed
40699932