European chemists get a new form of carbon

European chemists get a new form of carbon
European chemists get a new form of carbon

Another allotropic modification of carbon - a flat crystal lattice of squares, hexagons and octagons - exhibits pronounced metallic properties.

At the top of the illustration is a diagram of the new crystal structure, at the bottom is its picture taken by an electron microscope

Carbon is a unique chemical element, the atoms of which are capable of forming a variety of compounds with each other and create a whole range of completely different simple substances, such as graphite, diamond and a number of other, less common variants. A couple of decades ago, another well-known allotropic modification of carbon, graphene, was obtained. It is a flat hexagonal crystal lattice one atom thick.

Theoretically, other variants of compounds of carbon atoms into a planar structure are also possible, although so far it has not been possible to obtain them in practice. Only now one of them was created by scientists from Germany and Finland: this crystal lattice is formed not only by hexagons, but also by squares and octagons with four and eight vertices, respectively. An article by Michael Gottfried and his colleagues is published in Science.

The conventional unit of such a structure is biphenylene molecules containing tetra- and hexagonal rings. Therefore, the authors named it the Biphenylene Network (BN). It was obtained by depositing biphenylene on a smooth gold substrate: first, these molecules bind into chains, after which the individual chains merge into a plane. It is curious that the chains are chiral - they can exist in two mirror versions - and connect only when they coincide with each other.

The very first studies of the properties of BN showed that they differ markedly from graphene and other forms of carbon. Such structures have pronounced metallic characteristics: even with a width of only 21 atoms, the lattice conducts electricity, although the same graphene remains a semiconductor. According to scientists, such features make BN a promising material for new types of electronics and battery anodes.

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