Here in the UK, Channel 4 just screened an interesting documentary. Good viewing and challenges what seems to have become the accepted view that global warming is caused by man-made CO2 emissions. Instead, the programme points out that climate change has always been with us (including a medieval warm period, even balmier than today, and a mini ice-age in the seventeenth century when the River Thames froze so solid that fairs were regularly held on the ice). The programme presents some evidence to suggest that the rise in carbon dioxide lags behind temperature rises by 800 years and therefore can't be the cause of it. It also suggests that man-made sources of carbon dioxide are dwarfed by natural sources and that the source of variation in temperature is really linked to variations in sun activity.
The programme suggests that we can hardly be surprised when "environmental journalists" whose continued employment requires publication of stories produce newsworthy doom-laden stories. After all, why would the media publish stories from such journalists the gist of which is there is no need to panic because climate variation is nothing to do with us.
Anyway, if you are able, see the programme again in the UK on More4 (Monday 12 March 2007, 10.00pm): "Polemical film challenging the consensus that man-made CO2 is heating up the earth. Featuring leading academics, the film questions the science behind the accepted reasons for global warming and argues other explanations for climate change are not being properly aired".
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)
Many agree that replacing conventional petrol driven cars with hydrogen is a good idea provided the hydrogen does not originate in a process involving oil as the only product from hydrogen burning is water, rather than carbon dioxide.
However the road to hydrogen-powered vehicles will not be easy, industry experts state. Representatives of European and American car and energy companies at the National Hydrogen Association convention said hydrogen technology is feasible, but faces big challenges to become commercially viable.
"We all have our homework to do in the coming years," said Klaus Bonhof, manager of the alternative fuels division of DaimlerChrysler AG. "We must produce technology viable in volume, and that technology must be commercially applicable."
Several car compnaies had hydrogen-powered vehicles on display at the conference, but all have similar technological challenges, including costs that range up to a million dollars a piece and limited range on a hydrogen fill-up. While a hydrogen-pwered car can travel 45 to 50 miles on a gallon, the fuel tank only provide a range of 125 to 150 miles. This is because hydrogen is put in a car as a liquid at very low temperatures, but reverts to a gas as on warming. The gas produced has to be vented while the car is not being used so that after a few days the tank will be empty.
The industry is working on this and BMW vice president of clean technology Frank Ochmann said BMW is testing an insulated tank that would keep hydrogen cold and liquid. "If you put in this tank a snowman, it would take about thirteen years to melt down," he said.
Developing hydrogen fuel station is easy part, experts said as hydrogen is already shipped to industrial users in tanks or moved through pipelines. BMW estimates it will be 2025 before hydrogen powered vehicles are commonly produced and sold.
An egg-shaped fullerene, or "buckyball egg" has been made and characterized by chemists in America at UC Davis (California), Virginia Tech, and Emory and Henry College in Virginia. They were trying to encapsulate terbium atoms within fullerenes but instead encapsulated terbium nitride within an egg-shaped fullerene.1
The compound Tb3N@C84 was synthesized using an arc-discharge generator by vaporizing composite graphite rods containing a mixture of Tb4O7, graphite, and iron nitride as catalyst in a low-pressure He/N2atmosphere. This gave a complex mixture of products and chromatography gave seven terbium-containing fractions, the fourth fraction of which contained two isomers of Tb3N@C84. Crystallographc studies show the compound from one angle in particular seems very egg shaped! Remarkable! The Tb3N unit is clearly visible (terbium in green and nitrogen in blue).
Until the publication of this work it was normally accepted that no two pentagons can touch in a fullerene and are always surrounded by hexagons. However in this case there are two pentagons (the 8 atoms at the pointy part of the egg at the top of the attached image) linked as a bent pentalene fragment.
- 1. 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)
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)
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.
Modern surface chemistry – fuel cells, artificial fertilizers and clean exhaust
The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry for 2007 to Gerhard Ertl of the Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany "for his studies of chemical processes on solid surfaces".
The Nobel Prize in Chemistry for 2007 is awarded for groundbreaking studies in surface chemistry. This science is important for the chemical industry and can help us to understand such varied processes as why iron rusts, how fuel cells function and how the catalysts in our cars work. Chemical reactions on catalytic surfaces play a vital role in many industrial operations, such as the production of artificial fertilizers. Surface chemistry can even explain the destruction of the ozone layer, as vital steps in the reaction actually take place on the surfaces of small crystals of ice in the stratosphere. The semiconductor industry is yet another area that depends on knowledge of surface chemistry.
It was thanks to processes developed in the semiconductor industry that the modern science of surface chemistry began to emerge in the 1960s. Gerhard Ertl was one of the first to see the potential of these new techniques. Step by step he has created a methodology for surface chemistry by demonstrating how different experimental procedures can be used to provide a complete picture of a surface reaction. This science requires advanced high-vacuum experimental equipment as the aim is to observe how individual layers of atoms and molecules behave on the extremely pure surface of a metal, for instance. It must therefore be possible to determine exactly which element is admitted to the system. Contamination could jeopardize all the measurements. Acquiring a complete picture of the reaction requires great precision and a combination of many different experimental techniques.
Gerhard Ertl has founded an experimental school of thought by showing how reliable results can be attained in this difficult area of research. His insights have provided the scientific basis of modern surface chemistry: his method-ology is used in both academic research and the indust-rial development of chemical processes. The approach developed by Ertl is based not least on his studies of the Haber-Bosch process, in which nitrogen is extracted from the air for inclusion in artificial fertilizers. This reaction, which functions using an iron surface as its catalyst, has enormous economic significance because the availability of nitrogen for growing plants is often restricted. Ertl has also studied the oxidation of carbon monoxide on platinum, a reaction that takes place in the catalyst of cars to clean exhaust emissions.
Only carbon from the Group 14 elements forms stable double bonds with oxygen under normal conditions. When frozen, carbon dioxide is known as "dry-ice". A non-molecular single-bonded crystalline form of carbon dioxide (phase V) exists at high pressure according to Italian and French researchers.1
Amorphous forms of silica (a-SiO2) and germania (a-GeO2) are known at ambient conditions but only recently has an amorphous, silica-like form of carbon dioxide, a-CO2. This is labelled a-carbonia and made by compression of CO2 at room temperature at pressures between 40 and 48 GPa (that's a staggering 400-500 thousand atmospheres).
During this compression, infrared spectra at temperatures up to 680 K show the progressive formation of C–O single bonds and the simultaneous disappearance of all infrared bands associated with molecular CO2. Raman and synchrotron X-ray diffraction measurements confirm the amorphous character of the CO2. Vibrational and diffraction data for a-SiO2 and a-GeO2 are closely related and calculations also suggest shows that a-CO2 is structurally homologous to a-silica (a-SiO2) and a-germania (a-GeO2).
This research helps to understanding the nature of the interiors of gas-giant planets where carbon dioxide may be squeezed at very high pressures. Maybe it could be used to make very hard glass because it is expected to be very stiff rather like diamond. The researchers ponder whether "small amounts of these new glasses could be of interest for technology applications like hard and resistant coatings for micro-electronics, for example."