Carbon

Single-bonded cubic form of nitrogen

Abstract: Nitrogen usually consists of molecules where two atoms are strongly triple-bonded. Here, we report on an allotropic form of nitrogen where all atoms are connected with single covalent bonds, similar to carbon atoms in diamond. The compound was synthesized directly from molecular nitrogen at temperatures above 2,000 K and pressures above 110 GPa using a laser-heated diamond cell

Single-bonded cubic form of nitrogen, Eremets, Mikhail I., Gavriliuk Alexander G., Trojan Ivan A., Dzivenko Dymitro A., and Boehler Reinhard , Nature Materials, 8/2004, Volume 3, Issue 8, p.558 - 563, (2004)

Tb3N@C84 :  An Improbable, Egg-Shaped Endohedral Fullerene that Violates the Isolated Pentagon Rule

Abstract.The structure of isomer 2 of Tb3N@C84 has been determined through single-crystal X-ray diffraction on Tb3N@C84·NiII(OEP)·2(C6H6). The carbon cage has a distinct egg shape due to the presence of a single pair of fused pentagons at one apex of the molecule. Thus, although 24 IPR structures are available to the C84 cage, Nature utilizes one of the 51 568 isomeric structures that do not conform to the IPR for this unusual molecule. The Tb3N portion of isomer 2 of Tb3N@C84 is strictly planar. One Tb atom is nestled within the fold of the fused pentagons, while the other Tb atoms are disordered over four pairs of sites.

Tb3N@C84 :  An Improbable, Egg-Shaped Endohedral Fullerene that Violates the Isolated Pentagon Rule, Beavers, Christine M., Zuo Tianming, Duchamp James C., Harich Kim, Dorn Harry C., Olmstead Marilyn M., and Balch Alan L. , Journal of the American Chemical Society, 09/2006, Volume 128, Issue 35, p.11352 - 11353, (2006)

BuckyEgg

BuckyEgg

BuckyEgg Tb3N@C84: image credit Mark Winter

Rover Senses Carbonates

Rover Senses Carbonates

This graph, consisting of data from the Mars Exploration Rover Spirit's mini-thermal emission spectrometer, shows the light, or spectral, signatures of carbonates - organic molecules common to Earth that form only in water. The detection of trace amounts of carbonates on Mars may be due to an interaction between the water vapor in the atmosphere and minerals on the surface.

Image credit: NASA/JPL/Arizona State University

Superconductivity in diamond

Abstract: Diamond is an electrical insulator well known for its exceptional hardness. It also conducts heat even more effectively than copper, and can withstand very high electric fields. With these physical properties, diamond is attractive for electronic applications, particularly when charge carriers are introduced (by chemical doping) into the system. Boron has one less electron than carbon and, because of its small atomic radius, boron is relatively easily incorporated into diamond; as boron acts as a charge acceptor, the resulting diamond is effectively hole-doped. Here we report the discovery of superconductivity in boron-doped diamond synthesized at high pressure (nearly 100,000 atmospheres) and temperature (2,500–2,800 K). Electrical resistivity, magnetic susceptibility, specific heat and field-dependent resistance measurements show that boron-doped diamond is a bulk, type-II superconductor below the superconducting transition temperature Tc about 4 K; superconductivity survives in a magnetic field up to Hc2(0) 3.5 T. The discovery of superconductivity in diamond-structured carbon suggests that Si and Ge, which also form in the diamond structure, may similarly exhibit superconductivity under the appropriate conditions.

Superconductivity in diamond, Ekimov, E. A., Sidorov V. A., Bauer E. D., Mel'nik N. N., Curro N. J., Thompson J. D., and Stishov S. M. , Nature, 4/2004, Volume 428, Issue 6982, p.542 - 545, (2004)

Soot climate forcing via snow and ice albedos

Abstract: plausible estimates for the effect of soot on snow and ice albedos (1.5% in the Arctic and 3% in Northern Hemisphere land areas) yield a climate forcing of +0.3 W/m2 in the Northern Hemisphere. The “efficacy” of this forcing is ∼2, i.e., for a given forcing it is twice as effective as CO2 in altering global surface air temperature. This indirect soot forcing may have contributed to global warming of the past century, including the trend toward early springs in the Northern Hemisphere, thinning Arctic sea ice, and melting land ice and permafrost. If, as we suggest, melting ice and sea level rise define the level of dangerous anthropogenic interference with the climate system, then reducing soot emissions, thus restoring snow albedos to pristine high values, would have the double benefit of reducing global warming and raising the global temperature level at which dangerous anthropogenic interference occurs. However, soot contributions to climate change do not alter the conclusion that anthropogenic greenhouse gases have been the main cause of recent global warming and will be the predominant climate forcing in the future.

Soot climate forcing via snow and ice albedos, Hansen, J. , Proceedings of the National Academy of Sciences, 01/2004, Volume 101, Issue 2, p.423 - 428, (2004)

Scientists create fifth form of carbon

Scientists create fifth form of carbon

Magnetic carbon 'nanofoam' could find medical applications.

Researchers have created a new form of carbon: a spongy solid that is extremely lightweight and, unusually, attracted to magnets. The foam could one day help treat cancer and enhance brain scans, say the inventors.

Scientists create fifth form of carbon, Giles, Jim , news@nature, 3/2004, (2004)

Mosaic of river channel and ridge area on Titan

Mosaic of river channel and ridge area on Titan

Mosaic of river channel and ridge area on Titan. Credit: ESA/NASA/JPL/University of Arizona: http://www.esa.int/SPECIALS/Cassini-Huygens/SEM48881Y3E_0.html

Ig Nobel Prize for chemistry 2009

The 2009 chemistry prize goes to Javier Morales, Miguel Apátiga, and Victor M. Castaño (Universidad Nacional Autónoma de México) for creating diamonds from liquid — specifically from tequila.

Abstract from "Growth of Diamond Films from Tequila," Javier Morales, Miguel Apatiga and Victor M. Castano, 2008, arXiv:0806.1485. Diamond thin films were growth using Tequila as precursor by Pulsed Liquid Injection Chemical Vapor Deposition (PLI-CVD) onto both silicon (100) and stainless steel 304 at 850 C. The diamond films were characterized by Scanning Electron Microscopy (SEM) and Raman spectroscopy. The spherical crystallites (100 to 400 nm) show the characteristic 1332 cm-1 Raman band of diamond.

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Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.