Tetrahedrally Coordinated sp<sup>3</sup>-Hybridized Carbon in Sr<sub>2</sub>CO<sub>4</sub> Orthocarbonate at Ambient Conditions
Dominik Spahr, Jannes Binck, Lkhamsuren Bayarjargal, Rita Luchitskaia, W. Morgenroth, Davide Comboni, Victor Milman, Björn Winkler
Abstract
We have synthesized the orthocarbonate Sr2CO4, in which carbon is tetrahedrally coordinated by four oxygen atoms, at moderately high pressures [20(1) GPa] and high temperatures (≈3500 K) in a diamond anvil cell by reacting a SrCO3 single crystal with SrO powder. We show by synchrotron powder X-ray diffraction, Raman spectroscopy, and density functional thoery calculations that this phase, and hence sp3-hybridized carbon in a CO44– group, can be recovered at ambient conditions. The C–O bond distances are all of similar lengths [≈1.41(1) Å], and the O–C–O angles deviate from the ideal tetrahedral angle by a few degrees only.