Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 

Russian Scientists Created A Chemical Space Mapping Method And Cracked The Mystery Of Mendeleev Numbers

Scientists had long tried to come up with a system for predicting the properties of materials based on their chemical composition until they set sights on the concept of a chemical space which places materials in a reference frame such that neighboring chemical elements and compounds plotted along its axes have similar properties. 

This idea was first proposed in 1984 by the British physicist, David G. Pettifor, who assigned a Mendeleev number (MN) to each element. Yet the meaning and origin of MNs were unclear. Scientists from the Skolkovo Institute of Science and Technology (Skoltech) puzzled out the physical meaning of the mysterious MNs and suggested calculating them based on the fundamental properties of atoms. 

They showed that both MNs and the chemical space built around them were more effective than empirical solutions proposed until then. Their research supported by a grant from the Russian Science Foundation’s (RSF) World-class Lab Research Presidential Program was presented in The Journal of Physical Chemistry C.

Systematizing the enormous variety of chemical compounds, both known and hypothetical, and pinpointing those with a particularly interesting property is a tall order. Measuring the properties of all imaginable compounds in experiment or calculating them theoretically is downright impossible, which suggests that the search should be narrowed down to a smaller space.

David G. Pettifor put forward the idea of a chemical space in the attempt to somehow organize the knowledge about material properties. The chemical space is basically a reference frame where elements are plotted along the axes in a certain sequence such that the neighboring elements, for instance Na and K, have similar properties. The points within the space represent compounds, so that the neighbors, for example NaCl and KCl, have similar properties, too. In this setting, one area is occupied by superhard materials and another by ultrasoft ones. Having the chemical space at hand, one could create an algorithm for finding the best material among all possible compounds of all elements. To build their “smart” map, Skoltech scientists, Artem R. Oganov and Zahed Allahyari, came up with their own universal approach that boasts the highest predictive power as compared to the best known methods.

For many years scientists were clueless as to how Pettifor derived his MNs (if not empirically), while their physical meaning remained a nearly “esoteric” mystery for years.

“I had been wondering about what these MNs are for 15 years until I realized that they are most likely rooted in the atom’s fundamental properties, such as radius, electronegativity, polarizability, and valence. While valence is variable for many elements, polarizability is strongly correlated with electronegativity. This leaves us with radius and electronegativity which can be reduced to one property through a simple mathematical transformation. And here we go: we obtain an MN that turns out to be the best way to describe all the properties of an atom, and by a single number at that,” explains Artem R. Oganov, RSF grant project lead, a professor at Skoltech and MISiS, a Member of the Academia Europaea, a Fellow of the Royal Society of Chemistry (FRSC) and a Fellow of the American Physical Society (APS).

The scientists used the calculated MNs to arrange all the elements in a sequence that posed as the abscissa and ordinate axes at the same time. Each point in space In corresponds to all compounds of the corresponding elements. In this space, using measured or predicted properties of compounds, one can map any specific characteristic, for example, hardness, magnetization, enthalpy of formation, etc. A property map thus produced clearly showed the areas containing the most promising compounds, such as superhard or magnetic materials.

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 

Energy Resources Aotearoa: New Law On Decommissioning Could Be Costly Overkill
A new law on decommissioning oil and gas fields passed by Parliament today has good intentions but is overkill, according to Energy Resources Aotearoa. "We strongly support operators taking responsibility and paying the costs for decommissioning, which is what all good operators do," says chief executive John Carnegie... More>>


Commerce Commission: News Publishers’ Association Seeks Authorisation To Engage In Collective Bargaining

News Publishers’ Association of New Zealand Incorporated seeks authorisation and provisional authorisation to engage in collective bargaining with Facebook and Google. The Commerce Commission has received applications from News Publishers’ Association of New Zealand Incorporated (NPA) seeking authorisation and provisional authorisation on behalf of itself... More>>


Reserve Bank: MPC Continues To Reduce Monetary Stimulus
The Monetary Policy Committee agreed to raise the Official Cash Rate (OCR) to 0.75 per cent. The Committee agreed it remains appropriate to continue reducing monetary stimulus so as to maintain price stability and support maximum sustainable employment... More>>

PriceSpy: Producer Prices Increase
New Black Friday and Covid-19 Report* released by PriceSpy says people’s fear of stepping inside physical shops during big sales events like Black Friday has risen since last year; Kiwis are still planning to shop, but more than ever will do it online this year... More>>

NZ Skeptics Society: Announce Their 2021 Awards, And Dr Simon Thornley Wins The Bent Spoon

Every year the New Zealand Skeptics presents its awards to people and organisations who have impressed us or dismayed us, and this year it’s been hard to pick our winners because there have been so many choices!.. More>>



REINZ: Sales Volumes Leveling Out

Data released today by the Real Estate Institute of New Zealand (REINZ) shows there were 44 fewer lifestyle property sales (-2.6%) for the three months ended October 2021 than for the three months ended September 2021... More>>


BNZ: Auckland Retail Card Spending Bounces Back In Step Two
Bank of New Zealand (BNZ) card spending data released today shows one week of retail therapy at Alert Level 3 Step 2 has been enough to raise card spending in Auckland to levels greater than before the Delta lockdown... More>>