Why is carbon considered a unique element

Element between the chairs

He doesn't care about gold, silver leaves him cold, and platinum doesn't really turn him on either. Harald Hillebrecht only really gets going with one element.

"There is really no more exciting element than the element boron. We don't know of any element that makes such different compositions. That is really unique!"

The reason: From a chemical point of view, boron is an eccentric - not fish, not meat. Sometimes it behaves almost like a metal, at other times it forms bonds like carbon. And just five electrons circle in the shell of the boron atom. Hillebrecht, chemistry professor at the University of Freiburg, attests that he has a pronounced electron deficiency.

"And this deficiency is a real advantage for us. With this deficiency it just has to be creative. And no other element is as creative as boron."

In other words: boron can be chemically bonded with all possible substances - be it titanium, nitrogen or carbon. And because boron lacks electrons, it clings to its own and foreign electrons as tightly as the mother hen her chicks. In other words, boron tends to bond firmly - so tightly that this bond cannot be broken so easily by heat and acid, or by bumping and scratching. Compounds such as boron nitride and boron carbide are among the hardest, most heat-resistant and toughest materials available on the market. They are used when handling red-hot molten steel and aluminum. In cars, they can be found in spark plugs and in the lambda probe of the catalytic converter. The military uses them for armor plates and bulletproof vests. And then there's one more thing that DIY enthusiasts know too.

"Sandblasting nozzles. Not only what is blown with them is sanded, but also where it passes. That has to be extremely resistant. And of course you don't feel like opening the next nozzle after two minutes. It has to be Hold on for a while. And these nozzles are made of boron carbide. "

The disadvantage: workpieces made of boron carbide or boron nitride are not cheap goods. Process temperatures of more than 1000 degrees are required to manufacture them. The energy costs are correspondingly high. Nevertheless, the experts hope that the light and hard boron compounds will increasingly replace the conventional, oxygen-containing ceramics over the next few years.

And: There are also many new application ideas - for example the thermoelectric components. This is the name given to semiconductor materials that generate electricity directly from heat. Today, a lot of waste heat evaporates from chimneys and chimneys, for example in a waste incineration plant. This unused energy can be recovered - at least that is the vision: a thermoelectric semiconductor should extract some of the heat from the hot exhaust gases and turn it into electricity, says Harald Hillebrecht.

"But how it is with exhaust gases: They are chemically extremely aggressive. And you have to take something that is stable there. And the borides and the boron itself are. And that is why they are good candidates."

A huge market - if you only knew how to do it. Because in order to make the boron compounds, the borides, electrically active, they have to be seasoned with other substances, they have to be doped, as the expert says. However, it is not yet clear which types of atoms are suitable for doping in which concentrations. Some basic research is still necessary for chemist Hillebrecht.

"Specifically, we don't have anything yet, but that doesn't bother us at all. Something will come out of it."

But whether something will come out in two years or five - the Freiburg boron expert doesn't know either.