Carbon enters silica forming a cristobalite-type CO2-SiO2 solid solution.
Extreme conditions permit unique materials to be synthesized and can significantly update our view of the periodic table. In the case of group IV elements, carbon was always considered to be distinct with respect to its heavier homologues in forming oxides. Here we report the synthesis of a crystalline CO2-SiO2 solid solution by reacting carbon dioxide and silica in a laser-heated diamond anvil cell (P = 16-22 GPa, T>4,000 K), showing that carbon enters silica. Remarkably, this material is recovered to ambient conditions. X-ray diffraction shows that the crystal adopts a densely packed α-cristobalite structure (P4(1)2(1)2) with carbon and silicon in fourfold coordination to oxygen at pressures where silica normally adopts a sixfold coordinated rutile-type stishovite structure. An average formula of C0.6(1)Si0.4(1)O2 is consistent with X-ray diffraction and Raman spectroscopy results. These findings may modify our view on oxide chemistry, which is of great interest for materials science, as well as Earth and planetary sciences.
1] Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), Sesto Fiorentino 50019, Italy [2] European Laboratory for Non-Linear Spectroscopy (LENS), Sesto Fiorentino 50019, Italy.
Mario
M
Santoro
1] Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), Sesto Fiorentino 50019, Italy [2] European Laboratory for Non-Linear Spectroscopy (LENS), Sesto Fiorentino 50019, Italy.
Federico A
FA
Gorelli
1] European Laboratory for Non-Linear Spectroscopy (LENS), Sesto Fiorentino 50019, Italy [2] Dipartimento di Chimica dell'Università di Firenze, Sesto Fiorentino 50019, Italy.
Roberto
R
Bini
European Synchrotron Radiation Facility, 38043 Grenoble CEDEX 9, France.
Ashkan
A
Salamat
European Synchrotron Radiation Facility, 38043 Grenoble CEDEX 9, France.
Gaston
G
Garbarino
Laboratoire Charles Coulomb, UMR 5221, Centre National de la Recherche Scientifique (CNRS), Département Colloïdes, Verres et Nanomatériaux (CVN), Université Montpellier 2, 34095 Montpellier CEDEX 5, France.
Claire
C
Levelut
Institut Charles Gerhardt Montpellier, UMR 5253, Centre National de la Recherche Scientifique (CNRS), Equipe C2M, Université Montpellier 2, 34095 Montpellier CEDEX 5, France.
Olivier
O
Cambon
Institut Charles Gerhardt Montpellier, UMR 5253, Centre National de la Recherche Scientifique (CNRS), Equipe C2M, Université Montpellier 2, 34095 Montpellier CEDEX 5, France.
Julien
J
Haines
D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D007834:Lasers; D011312:Pressure; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
D002245:Carbon Dioxide; D002244:Carbon; D012822:Silicon Dioxide