The discovery of the previously unknown "black nitrogen" resolved the paradox of the Mendeleev system

Researchers from the University of Bayreuth (Germany) can be proud of a double achievement. Experimenting with nitrogen, they got it in a hitherto unknown form, a new substance. These are two-dimensional crystals of nitrogen atoms connected in a zigzag pattern, which makes the entire structure resemble graphene, but much more like black phosphorus. Hence the name - the researchers dubbed the novelty "black nitrogen".

One of the properties of the Periodic Table of Chemical Elements is the presence of the periods themselves, by which it is possible to predict the repetition of the properties of the first elements in those behind them. This rule of periodicity also applies to allotropy, the existence of such forms of matter that are similar to heavier elements in this period. For example, ozone is an allotrope of oxygen, and graphite and diamond are allotropes of carbon.

There are many such allotropes, and only for nitrogen, scientists knew only one - the substance dinitrogen. Because of this, nitrogen looked like a black sheep, broke an important rule and was a kind of exception. But with the receipt of "black nitrogen" everything fell into place - the nitrogen allotrope exists, the rule works. This is the second achievement of German scientists.

Alas, the discovery has no practical benefit yet. To obtain "black nitrogen", a diamond anvil was used with a pressure of 1.4 million atmospheres and a temperature above 4000 ° C. In their absence, the unstable substance quickly collapses, so so far it has not even been possible to measure its properties. But in this case, the very fact of discovery is important - scientists are convinced that they are moving in the right direction.