High Pressure Structural Changes in Amorphous Polymeric Carbon Monoxide by Combined Infrared Spectroscopy and X-ray Diffraction

Year: 2022

Authors: Santoro M., Bini R., Ceppatelli M., Garbarino G., Gorelli F.A., Hanfland M., Scelta D.

Autors Affiliation: Consiglio Nazionale Delle Ricerche – Istituto Nazionale di Ottica, CNR-INO, Via Nello Carrara 1, (FI), Sesto Fiorentino, Italy; European Laboratory for Nonlinear Spectroscopy, LENS, via Nello Carrara 1, (FI), Sesto Fiorentino, 50019, Italy; Dipartimento di Chimica Ugo Schiff, Universita di Firenze, via della Lastruccia 3, (FI), Sesto Fiorentino, 50019, Italy; Consiglio Nazionale Delle Ricerche – Istituto di Chimica Dei Composti OrganoMetallici, CNR-ICCOM, Via Madonna del Piano 10, (FI), Sesto Fiorentino, 50019, Italy; European Synchrotron Radiation Facility, ESRF, 71 Avenue des Martyrs, CS40220, Cedex 9, Grenoble, 38043, France; Center for High Pressure Science Technology Advanced Research, 1690 Cailun Road, Shanghai, 201203, China

Abstract: The high pressure transformation of carbon monoxide into an amorphous polymeric material (a-pCO) is known since decades, yet the determination of its local structure is made difficult by the strong photoreactivity of this material along with the high hygroscopicity of the recovered samples. While accurate, nondestructive IR spectroscopy measurements at a few GPa show that a-pCO is a complex solid dominated by the sp2 hybridization for C and with oxygen forming both single and double bonds with carbon, the potential evolution of this chemical structure at higher pressures is hitherto terra incognita. Here we report a high pressure investigation of pCO up to 56 GPa, at room temperature, based on in situ IR spectroscopy and synchrotron X-ray diffraction (XRD) measurements in diamond anvil cells (DACs). Our study shows that this material remains amorphous up to the maximum investigated pressure, with sp2 C substantially converting to sp3 C upon increasing pressure above 12-13 GPa. This occurrence indicates that unsaturated a-pCO modifies with pressure toward an entirely single bonded amorphous material similarly to its theoretically predicted crystalline counterpart.


Volume: 126 (28)      Pages from: 11840  to: 11845

More Information: We thank the European Laboratory for Nonlinear Spectroscopy (LENS) for hosting part of the research, the Fondazione Cassa di Risparmio di Firenze for the strong support through the HP-PHOTOCHEM and SALUS Grants, the Project “GreenPhos-alta pressione” by the Ministero dell´Istruzione, dell´Universita e della Ricerca (MIUR), the Deep Carbon Observatory (DCO) initiative under the Project “Physics and Chemistry of Carbon at Extreme Conditions”, and the ESRF synchrotron for providing access to the ID15B beamline and for financial support under the Proposal Number CH-5800.
KeyWords: Amorphous materials; Chemical bonds; High pressure engineering; Infrared spectroscopy; Nondestructive examination; Spacecraft instruments; X ray diffraction
DOI: 10.1021/acs.jpcc.2c03204