Search: Analytical chemistry, Carbon
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 cellSingle-bonded cubic form of nitrogen, , Nature Materials, 8/2004, Volume 3, Issue 8, p.558 - 563, (2004)
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, , Journal of the American Chemical Society, 09/2006, Volume 128, Issue 35, p.11352 - 11353, (2006)
A NASA press release indicates that NASA's Spirit, the first of two Mars Exploration Rovers on the surface within Mars' Gusev crater, has identified carbonate minerals "in the rover's first survey of the site with its infrared sensing instrument, called the miniature thermal emission spectrometer or Mini-TES. Carbonates form in the presence of water, but it's too early to tell whether the amounts detected come from interaction with water vapor in Mars' atmosphere or are evidence of a watery local environment in the past, scientists emphasized."
"We came looking for carbonates. We have them. We're going to chase them," said Dr. Phil Christensen of Arizona State University, Tempe, leader of the Mini-TES team. Previous infrared readings from Mars orbit have revealed a low concentration of carbonates distributed globally. Christensen has interpreted that as the result of dust interaction with atmospheric water. First indications are that the carbonate concentration near Spirit may be higher than the Mars global average.
After the rover drives off its lander platform, infrared measurements it takes as it explores the area may allow scientists to judge whether the water indicated by the nearby carbonates was in the air or in a suspected ancient lake. http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040109a/graph-carb...
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
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, , news@nature, 3/2004, (2004)