Polycarbonyl

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Polycarbonyl, (also known as polymeric-CO, p-CO or poly-CO) is a solid metastable and explosive polymer of carbon monoxide.[1] The polymer is produced by exposing carbon monoxide to high pressures. The structure of the solid appears amorphous, but may include a zig zag of equally spaced CO groups.[2]

Formation

Poly-CO can be produced at pressures of 5.2 GPa. Polymerisation is catalysed by blue light at slightly lower pressures in the δ-phase of solid CO.[3] Another white phase can be made at higher temperatures at 6 or 7 GPa.[1] Poly-CO appears to be a yellow to dark red amorphous phase.[4] Whereas the white phase appears to be crystalline.[1]

R. J. Mills was the first to discover this solid. It was produced in a tungsten carbide anvil. Originally this was thought to be polymeric carbon suboxide, but the formation does not yield any gas byproduct such as carbon dioxide.[5] The yield of the solid can be up to 95%.[6]

Properties

The polymer is stable above about 80K. Below this temperature the ε form of solid molecular CO is formed instead. When the pressure is released the polymer remains stable at atmospheric pressure. The solid dissolves in water, alcohol and acetone.[5] When exposed to the atmosphere it is hydroscopic, becomes gluey, and changes colour, becoming darker.[6] The reaction with water produces carboxylic groups.[7]

[8]

The solid stores a high energy. It can decompose explosively forming glassy carbon and carbon dioxide.[6] The energy density stored can be up to 8 kJ/g. During the decomposition the temperature can be 2500K.[6] The density is 1.65 gcm-3, however most of the solid produced is porous, so the true density is likely to be higher.[6]

Infrared spectroscopy shows bands at 650, 1210, 1440, 1650 and 1760 cm-1. The 1760 band is likely to be due to the -C-(C=O)-C- structure.[3] The 1600 is due to vibration of a C=C double bond.[6]

The solid is electrically insulating with an electronic gap energy of 1.9 eV.[3]

Nuclear magnetic resonance for the material made from 13CO shows sharp resonance at 223 ppm due to ester or lactone attached carbon, and 151 ppm due to C=C double bonds. There is also broad resonance at 109 and 189 ppm. Over time of a few days, the 223 ppm peak reduces and all the other features increase in strength.[6]

Structure

Ideas of the structure include a zig zag chain of CO pointing in opposite directions, or five atom rings connected by CO and C-C bonds. The rings are lactones of tetronic acid: -C:-(C=O)-(C-O-)-(C=O)-O-. Interconnections between the rings are zig zags of CO.[3]

Other ideas of the structure of the solid, include graphitic carbon with carbon dioxide under pressure, and a polymer with this C3O2 monomer: -(C=O)-O-(C-)=C<. Yet other ideas are that the solid is the same as the polymer of carbon suboxide with oxalic anhydride.[9]

References

  1. ↑ 1.0 1.1 1.2 Rademacher, N.; L. Bayarjargal, W. Morgenroth, B. Winkler, and J. Ciezak-Jenkins (2011). "Preparation and characterization of solid carbon monoxide at high pressure in the diamond anvil cell". Retrieved 30 May 2013. 
  2. ↑ Podeszwa, Rafa?; Rodney J. Bartlett (2003). "Crystal orbital study of polycarbonyl". International Journal of Quantum Chemistry 95 (4-5): 638–642. doi:10.1002/qua.10655. ISSN 0020-7608. 
  3. ↑ 3.0 3.1 3.2 3.3 Bernard, Stephane (Feb 1998). "DECOMPOSITION AND POLYMERIZATION OF SOLID CARBON MONOXIDE UNDER PRESSURE". Trieste. Retrieved 30 May 2013. 
  4. ↑ Rademacher, Nadine; Lkhamsuren Bayarjargal, Wolfgang Morgenroth, Jennifer Ciezak-Jenkins, Sasha Batyrev, Björn Winkler. "High Pressure Investigations of Liquid and Polymerized CO up to 20 GPa Using Pair Distribution Function Analysis". Retrieved 30 May 2013. 
  5. ↑ 5.0 5.1 Mills, R. L.; D. Schiferl, A. I. Katz, B. W. Olinger (1984). "NEW PHASES AND CHEMICAL REACTIONS IN SOLID CO UNDER PRESSURE". Le Journal de Physique Colloques 45 (C8): C8–187–C8–190. doi:10.1051/jphyscol:1984833. ISSN 0449-1947. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Lipp, Magnus J.; William J. Evans, Bruce J. Baer, Choong-Shik Yoo (2005). "High-energy-density extended CO solid". Nature Materials 4 (3): 211–215. doi:10.1038/nmat1321. ISSN 1476-1122. 
  7. ↑ Ceppatelli, Matteo; Anton Serdyukov, Roberto Bini, Hans J. Jodl (2009). "Pressure Induced Reactivity of Solid CO by FTIR Studies". The Journal of Physical Chemistry B 113 (19): 6652–6660. doi:10.1021/jp900586a. ISSN 1520-6106. 
  8. ↑ Katz, Allen I.; David Schiferl, Robert L. Mills (1984). "New phases and chemical reactions in solid carbon monoxide under pressure". The Journal of Physical Chemistry 88 (15): 3176–3179. doi:10.1021/j150659a007. ISSN 0022-3654. 
  9. ↑ Lipp, M.; W. J. Evans, V. Garcia-Baonza, H. E. Lorenzana (1998). "Carbon Monoxide: Spectroscopic Characterization of the High–Pressure Polymerized Phase". Journal of Low Temperature Physics 111 (3/4): 247–256. doi:10.1023/A:1022267115640. ISSN 0022-2291. 

Other reading

  • Batyrev, I. G.; W. D. Mattson, B. M. Rice (2012). "Modeling of Early Stages of Formation of Poly-CO". MRS Proceedings 1405. doi:10.1557/opl.2012.345. ISSN 1946-4274. 
  • Sun, Jian; Dennis D. Klug, Chris J. Pickard, Richard J. Needs (2011). "Controlling the Bonding and Band Gaps of Solid Carbon Monoxide with Pressure". Physical Review Letters 106 (14). doi:10.1103/PhysRevLett.106.145502. ISSN 0031-9007. 
Common oxides
Exotic oxides
Polymers
Compounds derived from oxides
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