TY  - JOUR
AU  - Spahr, Dominik
AU  - Bayarjargal, Lkhamsuren
AU  - Brüning, Lukas
AU  - Kovalev, Valentin
AU  - Wedek, Lena M.
AU  - Bykov, Maxim
AU  - Milman, Victor
AU  - Giordano, Nico
AU  - Winkler, Björn
AU  - Bykova, Elena
TI  - Synthesis and characterization of crystalline polymeric carbonic acid (H<sub>2</sub>CO<sub>3</sub>) with sp<sup>3−</sup>hybridized carbon at elevated pressures
JO  - Communications chemistry
VL  - 8
IS  - 1
SN  - 2399-3669
CY  - [London]
PB  - Macmillan Publishers Limited, part of Springer Nature
M1  - PUBDB-2025-03831
SP  - 237
PY  - 2025
N1  - We gratefully acknowledge funding from the DFG (WI1232, BA4020, and FOR2125/CarboPaT) and the DFG Emmy-Noether Program (projects BY101/2-1 and BY112/2-1). 
AB  - The existence of polymeric carbonic acid (H<sub>2</sub>CO<sub>3</sub>) at elevated pressures has been predicted, but has not been investigated experimentally. Here, polymeric carbonic acid containing sp3-hybridized carbon was synthesized and characterized at  ≈40 GPa. H<sub>2</sub>CO<sub>3</sub> single crystals were obtained by laser-heating a H<sub>2</sub>O + CO<sub>2</sub> mixture in a diamond anvil cell. The orthorhombic crystal structure (Cmc2<sub>1</sub> with Z = 4) was refined from synchrotron single crystal X-ray diffraction data and is in agreement with a structural model predicted earlier. The crystal structure of H<sub>2</sub>CO<sub>3</sub>-Cmc2<sub>1</sub> is characterized by [CO<sub>4</sub>]<sup>4−</sup> building blocks which are connected via corner sharing, forming chains along the c-axis. The combination of single crystal X-ray data with experimental Raman spectroscopy and DFT-calculations confirms that the structural model of H<sub>2</sub>CO<sub>3</sub>-Cmc2<sub>1</sub> is appropriate. The synthesis condition of polymeric carbonic acid points towards its potential existence in ice giants including the ones present in our solar system.  
LB  - PUB:(DE-HGF)16
C6  - pmid:40781154
DO  - DOI:10.1038/s42004-025-01614-y
UR  - https://bib-pubdb1.desy.de/record/637339
ER  -