Rhenium diboride

Silver shinny solid

Fixed

2400 ° C

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Rheniumdiborid ( ReB2 ) is a synthetically produced crystalline solid. It consists of the elements rhenium, and boron and having a comparatively high hardness such as diamond. In experiments it was possible to scratch diamond with Rheniumdiborid, which suggests that this substance has a higher hardness than diamond in at least one crystallographic direction (the c -axis).

History and production

Rheniumdiborid is a non-naturally occurring compound and was first synthesized in the 1960s. Its extreme hardness was only by a group of scientists led by Hsiu- Ying Chung of the University of California, Los Angeles, discovered and published in 2007. It is produced by the powder of the two output elements in the vacuum included in the quartz glass, for a period of five days at 950-1000 ° C to be heated. This Rheniumdiborid arises as a black powder. The reaction of rhenium and boron in the arc, however, leads to metal shiny pellets.

Unlike the production of artificial diamond or cubic boron nitride here no large pressure is required. This production process is cheaper and less complicated.

Properties

The bulk modulus of 360 GPa and Rheniumdiborid is located so close beneath the diamond measured at 442 GPa. At temperatures between 4.5 K and 6.3 K, the substance becomes superconducting; the Trirheniumborid ( Re3b ) has this property at about 4.7 K.