Letter

Nature 441, 857-860 (15 June 2006) | doi:10.1038/nature04879; Received 23 September 2005; Accepted 9 May 2006

Amorphous silica-like carbon dioxide

Mario Santoro1,2, Federico A. Gorelli1,2, Roberto Bini1,3, Giancarlo Ruocco2,4, Sandro Scandolo5 and Wilson A. Crichton6

  1. LENS, European Laboratory for Non-linear Spectroscopy and INFM, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy
  2. CRS-SOFT-INFM-CNR, c/o Università di Roma "La Sapienza", I-00185 Roma, Italy
  3. Dipartimento di Chimica dell'Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy
  4. Dipartimento di Fisica, Università di Roma "La Sapienza", I-00185 Roma, Italy
  5. The Abdus Salam International Centre for Theoretical Physics (ICTP) and INFM/Democritos National Simulation Center, 34014 Trieste, Italy
  6. European Synchrotron Research Facility, BP 220, F38043 Grenoble, France

Correspondence to: Mario Santoro1,2Federico A. Gorelli1,2 Correspondence and requests for materials should be addressed to M.S. (Email: santoro@lens.unifi.it) or F.A.G. (Email: gorelli@lens.unifi.it).

Among the group IV elements, only carbon forms stable double bonds with oxygen at ambient conditions. At variance with silica and germania, the non-molecular single-bonded crystalline form of carbon dioxide, phase V, only exists at high pressure1, 2, 3, 4, 5, 6, 7, 8, 9. The amorphous forms of silica (a-SiO2) and germania (a-GeO2) are well known at ambient conditions; however, the amorphous, non-molecular form of CO2 has so far been described only as a result of first-principles simulations9. Here we report the synthesis of an amorphous, silica-like form of carbon dioxide, a-CO2, which we call 'a-carbonia'. The compression of the molecular phase III of CO2 between 40 and 48 GPa at room temperature initiated the transformation to the non-molecular amorphous phase. Infrared spectra measured at temperatures up to 680 K show the progressive formation of C–O single bonds and the simultaneous disappearance of all molecular signatures. Furthermore, state-of-the-art Raman and synchrotron X-ray diffraction measurements on temperature-quenched samples confirm the amorphous character of the material. Comparison with vibrational and diffraction data for a-SiO2 and a-GeO2, as well as with the structure factor calculated for the a-CO2 sample obtained by first-principles molecular dynamics9, shows that a-CO2 is structurally homologous to the other group IV dioxide glasses. We therefore conclude that the class of archetypal network-forming disordered systems, including a-SiO2, a-GeO2 and water, must be extended to include a-CO2.

MORE ARTICLES LIKE THIS

These links to content published by NPG are automatically generated.

NEWS AND VIEWS

Phase transitions in the mantle

Nature News and Views (20 Jul 1989)

Amorphous materials Relaxing times for silicon

Nature Materials News and Views (01 Nov 2004)

See all 4 matches for News And Views

RESEARCH

Six-fold coordinated carbon dioxide VI

Nature Materials Letter (01 Jan 2007)

Pressure-induced amorphization of crystalline silica

Nature Letters to Editor (07 Jul 1988)

Transformation pathways of silica under high pressure

Nature Materials Article (01 Dec 2006)

See all 41 matches for Research

Extra navigation

.

naturejobs

ADVERTISEMENT