Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Changing gold

12.02.2007
Gold is not as noble and stable as it has been previously thought. This is the conclusion of an international team of researchers from Germany, France and Sweden who came to the ESRF to study the structure of this material at high pressure. They present their results in Physical Review Letters.

The uniqueness of gold and its appreciation as a valuable throughout history is closely related to its exceptional stability to chemical reactions and extreme pressures and temperatures. Gold was considered as a synonym of immovability and constancy (remember the wedding rings!). Indeed, at ambient pressure gold has been known to remain stable in a cubic crystalline phase to at least 180 GPa (one million eight hundred thousand atmospheres).

Scientists from the Bayerisches Geoinstitut and the University of Heidelberg (Germany), together with researchers from Sweden and the ESRF (France) have detected for the first time a phase transformation in gold using the synchrotron. The experiments have shown that at pressures above ~240 GPa gold adopts an hexagonal-close packed structure.

In order to carry out their experiments, scientists used two beamlines of the ESRF combined with a new instrument at the Bayerisches Geoinstitut. The sample was placed inside a diamond anvil cell, which was then electrically heated externally. This allowed them to study gold at the pressures of the Earth’s core, that is, at a depth of 5500 km from the surface.

Advances in high-pressure techniques require standards which are applicable at a multimegabar pressure range. Large pressure and temperature stability of the cubic gold phase and its high isothermal compressibility make gold an ideal material to be used as a pressure marker at high pressure- high temperature experiments at pressures above 100 GPa. The pressure-induced phase transition found in gold at pressure above 240 GPa places a “natural” limit on the application of cubic gold as a standard.

These results confirm the theoretical predictions about the phase changes in gold. “These new experimental and theoretical results remind us that there is no “absolute” unchangeable material, and the noblest of all metals, gold, is not an exception from this rule”, explains Leonid Dubrovinsky, main researcher.

Montserrat Capellas | alfa
Further information:
http://www.esrf.fr/news/pressreleases/changinggold/

More articles from Physics and Astronomy:

nachricht Two dimensional circuit with magnetic quasi-particles
22.01.2018 | Technische Universität Kaiserslautern

nachricht Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Thanks for the memory: NIST takes a deep look at memristors

22.01.2018 | Materials Sciences

Radioactivity from oil and gas wastewater persists in Pennsylvania stream sediments

22.01.2018 | Earth Sciences

Saarland University bioinformaticians compute gene sequences inherited from each parent

22.01.2018 | Life Sciences

VideoLinks Wissenschaft & Forschung
Overview of more VideoLinks >>>