Twisted [C 2 O 5 ] 2− -groups in Ba[C 2 O 5 ] pyrocarbonate

• Published in: Chemical communications (Cambridge, England) England), 2023-10, Vol.59 (80), p.11951-11954
• Main Authors: Spahr, Dominik, Bayarjargal, Lkhamsuren, Haussühl, Eiken, Luchitskaia, Rita, Friedrich, Alexandra, Milman, Victor, Fedotenko, Timofey, Winkler, Björn
• Format: Article
• Language: English
• Subjects: Anions; Crystal structure; Density functional theory; Diamond anvil cells; Laser beam heating; Single crystals; Synchrotron radiation; Synchrotrons
• ISSN: 1359-7345; 1364-548X
• DOI: 10.1039/d3cc03324d

The inorganic pyrocarbonate salt Ba[C 2 O 5 ] contains twisted pyrocarbonate anions ([C 2 O 5 ] 2− ), an atomic arrangement previously not observed in other pyrocarbonates. This unexpected additional structural degree of freedom points towards an enlarged chemical variability in this novel group of compounds. Ba[C 2 O 5 ] was synthesized in a laser-heated diamond anvil cell at 30(2) GPa by heating a mixture of Ba[CO 3 ] + CO 2 to ≈ 1500(200) K. Its crystal structure was solved from single crystal synchrotron X-ray diffraction data and confirmed by density functional theory-based calculations. The two planar [CO 3 ] 2− -groups of the [C 2 O 5 ] 2− -anion are strongly twisted around the bridging oxygen atom. Ba[C 2 O 5 ] has been observed in the pressure range of 5–30 GPa, where its symmetry is P 6/ m with Z = 12.