Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stony Brook University Geosciences Researchers Re-Establish the Structure of Magnesium Borohydride

17.12.2012
An international team led by Xiang-Feng Zhou and Artem R. Oganov, PhD, theoretical crystallographers in the Department of Geosciences and Department of Physics and Astronomy at Stony Brook University, have established the structure of one of the most important high-energy-density materials, magnesium borohydride or Mg(BH4)2. Their findings, “First-Principles Determination of the Structure of Magnesium Borohydride,” have been published in the December 13 edition of Physical Review Letters.
“Experimental crystal structure determination is often viewed as a routine task with a guaranteed correct result, but we successfully challenged the ‘experimental’ structure of ä-Mg(BH4)2 ,” said Zhou. “This material contains nearly 15 wt. % hydrogen, which makes this an important energy material,” added Oganov.

Structures of several modifications of Mg(BH4)2 were known from high-quality powder diffraction data, a rather standard method for determining crystal structures of materials. Researchers used Prof. Oganov’s breakthrough evolutionary method for crystal structure prediction, aiming to find the most stable structures of Mg(BH4)2 at different conditions.

To Zhou’s surprise, among the theoretically predicted structures he did not find the structure earlier proposed by experimentalists for the ä-phase. He then investigated the experimental structural model and found it to be very unfavorable compared to the theoretically predicted models. Even worse, the “experimental” structure was found to be unable to sustain its own lattice vibrations - predicted to fall apart as a result of atomic thermal motion. This indicates that the “experimental” structure is absolutely impossible – even as a metastable state.

Comparing the diffraction patterns of the theoretically predicted structure with experiments, Zhou realized that there is a perfect match. Subsequently, he found yet another structure that matches experimental data. Thus, there are at least three completely different crystal structures that match experimental diffraction data, but one of them – the one claimed by experimentalists – has been ruled out. The other two structures were shown to explain another mystery - the existence of two almost indistinguishable phases called ä and ä’ (previous experiments were unable to propose any solution for the latter). Zhou and colleagues determined the structures of these phases to have symmetries I41/acd and P-4.

“It is indeed surprising that experimental work, based on high quality data, failed to correctly solve these simple and highly symmetric crystal structures, containing only six non-hydrogen atoms,” said Zhou. “We were also surprised to see completely different structures having identical diffraction patterns. In such situations, which may be more common than we expect, theoretical structure searching will play a major role.”

“Crystal structure is the basis for understanding the behavior of materials,” said Oganov. “The possibility to predict crystal structures is a major breakthrough of our time and will prove crucial for the future discovery of new materials.”

| Newswise
Further information:
http://www.stonybrook.edu

More articles from Physics and Astronomy:

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

nachricht Physicists discover mechanism behind granular capillary effect
24.05.2017 | University of Cologne

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: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>